Not sure there is a way in 4.1.3 to get this info.if the Dial Plan report has suitbale info you may get it this way. The other way would be to get this information by SQl query if you know how.
You can in 5/6/7 but thats no good here :-)
You can go to the Unity tools though and run a subscriber dump for the Unity users. Its in UnityTool>Administration Tools>Subscriber information Dump.
or you can get the latest copy here
http://www.ciscounitytools.com/APP_subr_info_dump_3x.htm
Hope some of this helps
Paul