This blog post will assist you install and configure DualMaps add-on in Dekho 4.1.9
Step 2: Create a new folder in \Tomcat\webapps\ROOT\ directory named DekhoTools
Step 3: Unzip the files in that folder (DualMaps_V41.swf)
Step 4: Copy the icon file “pegman.png” in ..\Tomcat 7.0\webapps\Dekho\images\admin\tools (the icon that appears on the admin GUI)
Step 5: Copy the icon file “pegman.png” in ..\Tomcat 7.0\webapps\Dekho\images\user\tools (the icon that appears on the client)
Step 6: In Dekho Admin, go to Settings : Tools and add a new tool
Step 7: Pick the “pegman” icon
Step 8: Fill in the description and tool tip. The tool tip is the text that appears when you hover your mouse over the icon.
Step 9: In the URL field, type http://server:8080/DekhoTools/DualMaps_V41.swf
Step 10: Click [Save]
Step 11: Edit your Dekho map and attach your new DualMap tool, then click [Publish]
The Dual Maps tool only works when using a Map Template that contains a service with the projection Web Mercator Auxiliary Sphere. This limitation is a requirement of the various various target map systems (Bing, GoogleMaps, StreetView,..)
If you add the custom tool to a Map that uses a template containing a single map service (ex :GDA 94), the result will open but the contents of the tool remains blank.
The solution is to change the projection of the Map Service used in the template to Web Mercator Auxiliary Sphere.
An alternative to this is issue is to use the Google Street View tool (http://www.dekhoforum.com/downloads/customtools/dekho41.custom.streetview.zip) which works with services that are in GDA 94.