Index: src/main/java/org/apache/maven/plugin/idea/AbstractIdeaMojo.java
===================================================================
--- src/main/java/org/apache/maven/plugin/idea/AbstractIdeaMojo.java	(revision 559855)
+++ src/main/java/org/apache/maven/plugin/idea/AbstractIdeaMojo.java	(working copy)
@@ -50,14 +50,7 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
 
 /**
  * @author Edwin Punzalan
@@ -218,15 +211,103 @@
         if ( convertedAbsolutePath.startsWith( convertedBasedirAbsolutePath )
             && convertedAbsolutePath.length() > convertedBasedirAbsolutePath.length() )
         {
+            // simple case, path starts with basepath
             relative = convertedAbsolutePath.substring( convertedBasedirAbsolutePath.length() + 1 );
+            relative = StringUtils.replace( relative, "\\", "/" );
         }
         else
         {
-            relative = convertedAbsolutePath;
+            // it's more complex...
+            convertedAbsolutePath = StringUtils.replace( convertedAbsolutePath, "\\", "/" );
+            convertedBasedirAbsolutePath = StringUtils.replace( convertedBasedirAbsolutePath, "\\", "/" );
+
+            StringTokenizer baseTokens=new StringTokenizer(convertedBasedirAbsolutePath,"/",false);
+
+            int baseCount=baseTokens.countTokens();
+            List baseTokenList=new ArrayList(baseCount);
+            while(baseTokens.hasMoreTokens())
+            {
+                baseTokenList.add(baseTokens.nextToken());
+            }
+
+            StringTokenizer pathTokens=new StringTokenizer(convertedAbsolutePath,"/",false);
+
+            int pathCount=pathTokens.countTokens();
+            List pathTokenList=new ArrayList(pathCount);
+            while(pathTokens.hasMoreTokens())
+            {
+                pathTokenList.add(pathTokens.nextToken());
+            }
+
+            int maxCount=Math.max(baseTokenList.size(), pathTokenList.size());
+            int differIndex=-1;
+            for(int i=0;i<maxCount;i++)
+            {
+                if(i>=pathTokenList.size() || i>=baseTokenList.size())
+                {
+                    differIndex=i;
+                    break;
+                }
+                String basePart=(String) baseTokenList.get(i);
+                String pathPart=(String) pathTokenList.get(i);
+                if(!basePart.equals(pathPart))
+                {
+                    differIndex=i;
+                    break;
+                }
+            }
+            /*
+            if ( getLog().isDebugEnabled() )
+            {
+                getLog().debug( "Construction of relative path... differIndex="+differIndex);
+            }
+            */
+            if(differIndex<1)
+            {
+                // paths are either equal or completely different
+                relative=convertedAbsolutePath;
+            }
+            else
+            {
+                StringBuffer result=new StringBuffer();
+                int parentCount=baseTokenList.size()-differIndex;
+                /*
+                if ( getLog().isDebugEnabled() )
+                {
+                    getLog().debug( "parentCount="+parentCount);
+                }
+                */
+                boolean isFirst=true;
+                for(int i=0;i<parentCount;i++)
+                {
+                    // add parents
+                    if(isFirst)
+                    {
+                        isFirst=false;
+                    }
+                    else
+                    {
+                        result.append("/");
+                    }
+                    result.append("..");
+                }
+                for(int i=differIndex;i<pathTokenList.size();i++)
+                {
+                    // add the remaining path elements
+                    if(isFirst)
+                    {
+                        isFirst=false;
+                    }
+                    else
+                    {
+                        result.append("/");
+                    }
+                    result.append(pathTokenList.get(i));
+                }
+                relative=result.toString();
+            }
         }
 
-        relative = StringUtils.replace( relative, "\\", "/" );
-
         if ( getLog().isDebugEnabled() )
         {
             getLog().debug( "toRelative(" + basedir + ", " + absolutePath + ") => " + relative );