Index: src/main/org/apache/tools/ant/IntrospectionHelper.java
===================================================================
--- src/main/org/apache/tools/ant/IntrospectionHelper.java	(revision 426873)
+++ src/main/org/apache/tools/ant/IntrospectionHelper.java	(working copy)
@@ -279,6 +279,79 @@
     }
 
     /**
+     * Returns a list containing the (US lowercased) names of the 
+     * attributes for which property expansion should not take place.
+     * 
+     * <p>The attribute names are extracted from the name of the Methods
+     * returned by the invocation of the bean's method 
+     * <code>public java.lang.reflect.Method [] 
+     * getUnexpandedAttrSetters()</code>, if defined.
+     * The methods must start with <code>set</code>.</p>
+     * 
+     * <p>Ex.: (supposing the caller of this method is RuntimeConfigurable) 
+     * if an element has method <code>setMyAttr(String str)</code>
+     * and a method <code>getUnexpandedAttrSetters()</code> returning an array 
+     * containing the method <code>setUnexAttr</code> and for an element
+     * you define the attribute <code>unexattr=&quot;${path.separator}&quot;</code>, 
+     * the method's <var>str</var> parameter will contain the unexpanded string,
+     * that is &quot;${path.separator}&quot; instead of &quot;:&quot;.</p>
+     * 
+     * @param bean The element. Must not be <code>null</code>.
+     * @return The list of attribute names for which
+     *         property expansion shouldn't take place,
+     *         or <code>null</code> if the bean
+     *         doesn't define the list of corresponding methods
+     *         or the list is empty.
+     */
+    protected List unexpandedAttributes(Object bean) {
+        
+        Method m = null;
+        try {
+            m = bean.getClass().getMethod("getUnexpandedAttrSetters",null);
+        } catch (NoSuchMethodException nsme) {
+            return null;
+        }
+
+        Class returnType = m.getReturnType();
+
+        if ((returnType.getComponentType() != null)
+                && Method.class.isAssignableFrom(
+                    returnType.getComponentType())) {
+            // it's the right method
+            Object result = null;
+            try {
+                result = m.invoke(bean, new Object[] {});
+            } catch (InvocationTargetException ite) {
+            } catch (IllegalAccessException iae) {
+            }
+            if (result != null) {
+                Method [] ma = (Method []) result;
+                if (ma.length > 0) {
+                    List names = null;
+                    int curM = 0;
+                    while (curM < ma.length) {
+                        if (ma[curM] != null) {
+                            String mname = ma[curM].getName();
+                            if (mname.startsWith("set")) {
+                                String aname = getPropertyName(
+                                        mname,"set");
+                                if (names == null) {
+                                    names = new ArrayList();
+                                }
+                                names.add(aname);
+                            }
+                        }
+                        curM++;
+                    }
+                    return names;
+                }
+            }
+        }
+        
+        return null;
+    }
+
+    /**
      * Certain set methods are part of the Ant core interface to tasks and
      * therefore not to be considered for introspection
      *
Index: src/main/org/apache/tools/ant/RuntimeConfigurable.java
===================================================================
--- src/main/org/apache/tools/ant/RuntimeConfigurable.java	(revision 426873)
+++ src/main/org/apache/tools/ant/RuntimeConfigurable.java	(working copy)
@@ -357,13 +357,18 @@
         IntrospectionHelper ih =
             IntrospectionHelper.getHelper(p, target.getClass());
 
+        List unexpandedAttrs = ih.unexpandedAttributes(target);
+            
         if (attributeNames != null) {
             for (int i = 0; i < attributeNames.size(); i++) {
                 String name = (String) attributeNames.get(i);
                 String value = (String) attributeMap.get(name);
 
                 // reflect these into the target
-                value = p.replaceProperties(value);
+                if ((unexpandedAttrs == null) || !unexpandedAttrs.contains(
+                        name.toLowerCase(Locale.US))) {
+                    value = p.replaceProperties(value);
+                }
                 try {
                     ih.setAttribute(p, target, name, value);
                 } catch (UnsupportedAttributeException be) {
Index: src/main/org/apache/tools/ant/ProjectHelper.java
===================================================================
--- src/main/org/apache/tools/ant/ProjectHelper.java	(revision 426873)
+++ src/main/org/apache/tools/ant/ProjectHelper.java	(working copy)
@@ -22,6 +22,7 @@
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.util.Hashtable;
+import java.util.List;
 import java.util.Locale;
 import java.util.Vector;
 import org.apache.tools.ant.helper.ProjectHelper2;
@@ -307,13 +308,18 @@
         IntrospectionHelper ih =
             IntrospectionHelper.getHelper(project, target.getClass());
 
+        List unexpandedAttrs = ih.unexpandedAttributes(target);
+
         for (int i = 0; i < attrs.getLength(); i++) {
             // reflect these into the target
-            String value = replaceProperties(project, attrs.getValue(i),
-                                             project.getProperties());
+            String name = attrs.getName(i).toLowerCase(Locale.US);
+            String value = attrs.getValue(i);
+            if ((unexpandedAttrs == null) 
+                    || !unexpandedAttrs.contains(name)) {
+                value = project.replaceProperties(value);
+            }
             try {
-                ih.setAttribute(project, target,
-                                attrs.getName(i).toLowerCase(Locale.US), value);
+                ih.setAttribute(project, target, name, value);
 
             } catch (BuildException be) {
                 // id attribute must be set externally
Index: src/etc/testcases/core/customtasks.xml
===================================================================
--- src/etc/testcases/core/customtasks.xml	(revision 0)
+++ src/etc/testcases/core/customtasks.xml	(revision 0)
@@ -0,0 +1,25 @@
+<project name="customtasks-test" basedir=".">
+
+    <property name="tmp.dir" location="tmp"/>
+
+    <target name="unexpandedsetup">
+      <typedef name="notexpandeda"
+          classname="org.apache.tools.ant.CustomTasksTest$NotExpandedATask"
+          classpath="${build.tests.value}"/>
+    </target>
+
+    <property name="foo" value="bar"/>
+
+    <target name="unexpandedattr" depends="unexpandedsetup">
+      <notexpandeda prefix="prop1" expstring="${foo}" unexpstring="${foo}"/>
+      <fail>
+        <condition>
+          <not><and>
+            <equals arg1="${prop1.exp}" arg2="bar"/>
+            <equals arg1="${prop1.unexp}" arg2="$${foo}"/>
+          </and></not>
+        </condition>
+      </fail>
+    </target>
+
+</project>
Index: src/testcases/org/apache/tools/ant/CustomTasksTest.java
===================================================================
--- src/testcases/org/apache/tools/ant/CustomTasksTest.java	(revision 0)
+++ src/testcases/org/apache/tools/ant/CustomTasksTest.java	(revision 0)
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2006 The Apache Software Foundation
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+
+package org.apache.tools.ant;
+
+import org.apache.tools.ant.BuildFileTest;
+import java.lang.reflect.Method;
+
+/**
+ * 
+ */
+public class CustomTasksTest extends BuildFileTest {
+
+    public CustomTasksTest(String name) {
+        super(name);
+    }
+
+    public void setUp() {
+        configureProject("src/etc/testcases/core/customtasks.xml");
+    }
+
+    public static class NotExpandedATask extends Task {
+    	private String expString = null;
+    	private String unexpString = null;
+    	private String prefix = null;
+
+    	public void setExpString(String expString) {
+    		this.expString = expString;
+    	}
+
+    	public void setUnexpString(String unexpString) {
+    		this.unexpString = unexpString;
+    	}
+
+    	public void setPrefix(String prefix) {
+    		this.prefix = prefix;
+    	}
+
+    	public Method [] getUnexpandedAttrSetters() {
+            Method method = null;
+            try {
+                method = getClass().getMethod("setUnexpString", 
+                		new Class[] {String.class});
+            } catch (NoSuchMethodException nsme) {
+                throw new BuildException(nsme);
+            }
+    		return new Method[] {method};
+    	}
+
+    	public void execute() throws BuildException {
+    		if ((prefix == null) || (expString == null) || (unexpString == null)) {
+    			throw new BuildException("Bad test initialisation");
+    		}
+    		getProject().setNewProperty(prefix + ".exp", expString);
+    		getProject().setNewProperty(prefix + ".unexp", unexpString);
+    	}
+    }
+    /**
+     */
+    public void testUnexpandedAttr() {
+        executeTarget("unexpandedattr");
+    }
+}
+