Index: src/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java
===================================================================
--- src/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java	(Revision 1239338)
+++ src/java/org/apache/poi/hssf/usermodel/HSSFWorkbook.java	(Arbeitskopie)
@@ -36,9 +36,9 @@
 import org.apache.poi.ddf.EscherRecord;
 import org.apache.poi.hssf.OldExcelFormatException;
 import org.apache.poi.hssf.model.HSSFFormulaParser;
-import org.apache.poi.hssf.model.RecordStream;
 import org.apache.poi.hssf.model.InternalSheet;
 import org.apache.poi.hssf.model.InternalWorkbook;
+import org.apache.poi.hssf.model.RecordStream;
 import org.apache.poi.hssf.record.AbstractEscherHolderRecord;
 import org.apache.poi.hssf.record.BackupRecord;
 import org.apache.poi.hssf.record.DrawingGroupRecord;
@@ -66,9 +66,9 @@
 import org.apache.poi.hssf.util.CellReference;
 import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
+import org.apache.poi.ss.formula.FormulaType;
 import org.apache.poi.ss.usermodel.CreationHelper;
 import org.apache.poi.ss.usermodel.Row.MissingCellPolicy;
-import org.apache.poi.ss.formula.FormulaType;
 import org.apache.poi.ss.util.WorkbookUtil;
 import org.apache.poi.util.POILogFactory;
 import org.apache.poi.util.POILogger;
@@ -1687,4 +1687,17 @@
     public NameXPtg getNameXPtg(String name) {
         return workbook.getNameXPtg(name);
     }
+    
+	/**
+	 * Changes an external referenced file to another file.
+	 * A formular in Excel which refers a cell in another file is saved in two parts: 
+	 * The referenced file is stored in an reference table. the row/cell information is saved separate.
+	 * This method invokation will only change the reference in the lookup-table itself.
+	 * @param oldUrl The old URL to search for and which is to be replaced
+	 * @param newUrl The URL replacement
+	 * @return true if the oldUrl was found and replaced with newUrl. Otherwise false
+	 */
+    public boolean changeExternalReference(String oldUrl, String newUrl) {
+    	return workbook.changeExternalReference(oldUrl, newUrl);
+    }
 }
Index: src/java/org/apache/poi/hssf/model/LinkTable.java
===================================================================
--- src/java/org/apache/poi/hssf/model/LinkTable.java	(Revision 1239338)
+++ src/java/org/apache/poi/hssf/model/LinkTable.java	(Arbeitskopie)
@@ -464,4 +464,26 @@
 	private int findRefIndexFromExtBookIndex(int extBookIndex) {
 		return _externSheetRecord.findRefIndexFromExtBookIndex(extBookIndex);
 	}
+	
+	/**
+	 * Changes an external referenced file to another file.
+	 * A formular in Excel which refers a cell in another file is saved in two parts: 
+	 * The referenced file is stored in an reference table. the row/cell information is saved separate.
+	 * This method invokation will only change the reference in the lookup-table itself.
+	 * @param oldUrl The old URL to search for and which is to be replaced
+	 * @param newUrl The URL replacement
+	 * @return true if the oldUrl was found and replaced with newUrl. Otherwise false
+	 */
+	public boolean changeExternalReference(String oldUrl, String newUrl) {
+		for(ExternalBookBlock ex : _externalBookBlocks) {
+			SupBookRecord externalRecord = ex.getExternalBookRecord();
+			if (externalRecord.isExternalReferences() 
+				&& externalRecord.getURL().equals(oldUrl)) {
+				
+				externalRecord.setURL(newUrl);
+				return true;
+			}
+		}
+		return false;
+	}
 }
Index: src/java/org/apache/poi/hssf/model/InternalWorkbook.java
===================================================================
--- src/java/org/apache/poi/hssf/model/InternalWorkbook.java	(Revision 1239338)
+++ src/java/org/apache/poi/hssf/model/InternalWorkbook.java	(Arbeitskopie)
@@ -81,8 +81,8 @@
 import org.apache.poi.hssf.record.WriteAccessRecord;
 import org.apache.poi.hssf.record.WriteProtectRecord;
 import org.apache.poi.hssf.record.common.UnicodeString;
+import org.apache.poi.hssf.record.formula.FormulaShifter;
 import org.apache.poi.hssf.record.formula.NameXPtg;
-import org.apache.poi.hssf.record.formula.FormulaShifter;
 import org.apache.poi.hssf.record.formula.Ptg;
 import org.apache.poi.hssf.util.HSSFColor;
 import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalName;
@@ -2372,5 +2372,17 @@
             }
         }
     }
-
+    
+	/**
+	 * Changes an external referenced file to another file.
+	 * A formular in Excel which refers a cell in another file is saved in two parts: 
+	 * The referenced file is stored in an reference table. the row/cell information is saved separate.
+	 * This method invokation will only change the reference in the lookup-table itself.
+	 * @param oldUrl The old URL to search for and which is to be replaced
+	 * @param newUrl The URL replacement
+	 * @return true if the oldUrl was found and replaced with newUrl. Otherwise false
+	 */
+    public boolean changeExternalReference(String oldUrl, String newUrl) {
+    	return linkTable.changeExternalReference(oldUrl, newUrl);
+    }
 }
Index: src/java/org/apache/poi/hssf/record/SupBookRecord.java
===================================================================
--- src/java/org/apache/poi/hssf/record/SupBookRecord.java	(Revision 1239338)
+++ src/java/org/apache/poi/hssf/record/SupBookRecord.java	(Arbeitskopie)
@@ -18,6 +18,8 @@
 package org.apache.poi.hssf.record;
 
 import org.apache.poi.util.LittleEndianOutput;
+import org.apache.poi.util.POILogFactory;
+import org.apache.poi.util.POILogger;
 import org.apache.poi.util.StringUtil;
 
 /**
@@ -30,7 +32,9 @@
  *
  */
 public final class SupBookRecord extends StandardRecord {
-
+    private final static String PATH_SEPERATOR = System.getProperty("file.separator");
+    private final static POILogger logger = POILogFactory.getLogger(SupBookRecord.class);
+    
     public final static short sid = 0x01AE;
 
     private static final short SMALL_RECORD_SIZE = 4;
@@ -192,21 +196,48 @@
         return encodedUrl;
     }
     private static String decodeFileName(String encodedUrl) {
-        return encodedUrl.substring(1);
-        // TODO the following special characters may appear in the rest of the string, and need to get interpreted
-        /* see "MICROSOFT OFFICE EXCEL 97-2007  BINARY FILE FORMAT SPECIFICATION"
-        chVolume  1
-        chSameVolume  2
-        chDownDir  3
-        chUpDir  4
-        chLongVolume  5
-        chStartupDir  6
-        chAltStartupDir 7
-        chLibDir  8
-
-        */
+        /* see "MICROSOFT OFFICE EXCEL 97-2007  BINARY FILE FORMAT SPECIFICATION" */
+    	StringBuilder sb = new StringBuilder();
+        for(int i=1; i<encodedUrl.length(); i++) {
+        	char c = encodedUrl.charAt(i);
+        	switch (c) {
+        	case 1: // chVolume  1
+        		char driveLetter = encodedUrl.charAt(++i);
+        		if (driveLetter == '@') {
+        			sb.append("\\\\");
+        		} else {
+        			sb.append(driveLetter);
+        		}
+        		break;
+        	case 2: // chSameVolume  2
+        		sb.append(PATH_SEPERATOR);
+        		break;
+        	case 3: // chDownDir  3
+        		sb.append(PATH_SEPERATOR);
+        		break;
+        	case 4: // chUpDir  4
+        		sb.append(".." + PATH_SEPERATOR);
+        		break;
+        	case 5: // chLongVolume  5
+        		logger.log(POILogger.WARN, "Found unexpected key: ChLongVolume - IGNORING");
+        		break;
+        	case 6: // chStartupDir  6
+        	case 7: // chAltStartupDir 7
+        	case 8: // chLibDir  8
+        		logger.log(POILogger.WARN, "EXCEL.EXE path unkown - using this directoy instead: .");
+        		sb.append("." + PATH_SEPERATOR);
+        		break;
+        	default:
+        		sb.append(c);
+        	}
+        }
+        return sb.toString();
     }
     public String[] getSheetNames() {
         return field_3_sheet_names.clone();
     }
+    
+    public void setURL(String pUrl) {
+    	field_2_encoded_url = field_2_encoded_url.substring(0, 1) + pUrl; 
+    }
 }