For Debugging in Silverlight:
Step 1: Add your .xap file as webresource in crm.
Step 2.
Save and publish it
Step 3.
Click on url link .
Step 4.
New Window will open.
Step 5.
Now in Visual studio click on Tools->Attach to process
And attach to the iexplore.exe which show type:Silverlight,X86
Step 6. Apply break point and refresh the Silverlight open url page