--- src/java/org/apache/poi/POIDocument.java	(revision 655041)
+++ src/java/org/apache/poi/POIDocument.java	(working copy)
@@ -20,6 +20,7 @@ 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.Iterator;
 import java.util.List;
 
@@ -170,6 +171,11 @@ 
 		}
 	}
 	
+	public void write(OutputStream out)
+	{
+	    System.err.println("Not implemented in this class");
+	}
+	
 	/**
 	 * Writes out a given ProperySet
 	 * @param name the (POIFS Level) name of the property to write
--- src/scratchpad/src/org/apache/poi/hdgf/HDGFDiagram.java	(revision 655041)
+++ src/scratchpad/src/org/apache/poi/hdgf/HDGFDiagram.java	(working copy)
@@ -27,6 +27,7 @@ 
 import org.apache.poi.hdgf.streams.Stream;
 import org.apache.poi.hdgf.streams.StringsStream;
 import org.apache.poi.hdgf.streams.TrailerStream;
+import org.apache.poi.poifs.filesystem.DirectoryNode;
 import org.apache.poi.poifs.filesystem.DocumentEntry;
 import org.apache.poi.poifs.filesystem.POIFSFileSystem;
 import org.apache.poi.util.LittleEndian;
@@ -53,43 +54,47 @@ 
 	private PointerFactory ptrFactory;
 	
 	public HDGFDiagram(POIFSFileSystem fs) throws IOException {
-		super(fs);
-		
-		DocumentEntry docProps =
-			(DocumentEntry)filesystem.getRoot().getEntry("VisioDocument");
+	    this(fs.getRoot(), fs);
+	}
+	
+	public HDGFDiagram(DirectoryNode dir, POIFSFileSystem fs) throws IOException {
+	    super(fs);
 
-		// Grab the document stream
-		_docstream = new byte[docProps.getSize()];
-		filesystem.createDocumentInputStream("VisioDocument").read(_docstream);
-		
-		// Read in the common POI streams
-		readProperties();
-		
-		// Check it's really visio
-		String typeString = new String(_docstream, 0, 20);
-		if(! typeString.equals(VISIO_HEADER)) {
-			throw new IllegalArgumentException("Wasn't a valid visio document, started with " + typeString);
-		}
-		
-		// Grab the version number, 0x1a -> 0x1b
-		version = LittleEndian.getShort(_docstream, 0x1a);
-		// Grab the document size, 0x1c -> 0x1f
-		docSize = LittleEndian.getUInt(_docstream, 0x1c);
-		// ??? 0x20 -> 0x23
-		
-		// Create the Chunk+Pointer Factories for the document version
-		ptrFactory = new PointerFactory(version);
-		chunkFactory = new ChunkFactory(version);
-		
-		// Grab the pointer to the trailer
-		trailerPointer = ptrFactory.createPointer(_docstream, 0x24);
-		
-		// Now grab the trailer
-		trailer = (TrailerStream)
-			Stream.createStream(trailerPointer, _docstream, chunkFactory, ptrFactory);
-		
-		// Finally, find all our streams
-		trailer.findChildren(_docstream);
+	    DocumentEntry docProps =
+	        (DocumentEntry)dir.getEntry("VisioDocument");
+
+	    // Grab the document stream
+	    _docstream = new byte[docProps.getSize()];
+	    dir.createDocumentInputStream("VisioDocument").read(_docstream);
+
+	    // Read in the common POI streams
+	    readProperties();
+
+	    // Check it's really visio
+	    String typeString = new String(_docstream, 0, 20);
+	    if(! typeString.equals(VISIO_HEADER)) {
+	        throw new IllegalArgumentException("Wasn't a valid visio document, started with " + typeString);
+	    }
+
+	    // Grab the version number, 0x1a -> 0x1b
+	    version = LittleEndian.getShort(_docstream, 0x1a);
+	    // Grab the document size, 0x1c -> 0x1f
+	    docSize = LittleEndian.getUInt(_docstream, 0x1c);
+	    // ??? 0x20 -> 0x23
+
+	    // Create the Chunk+Pointer Factories for the document version
+	    ptrFactory = new PointerFactory(version);
+	    chunkFactory = new ChunkFactory(version);
+
+	    // Grab the pointer to the trailer
+	    trailerPointer = ptrFactory.createPointer(_docstream, 0x24);
+
+	    // Now grab the trailer
+	    trailer = (TrailerStream)
+	    Stream.createStream(trailerPointer, _docstream, chunkFactory, ptrFactory);
+
+	    // Finally, find all our streams
+	    trailer.findChildren(_docstream);
 	}
 
 	/**