I have both a Google voice number and a Gizmo 5 number, and in the past -on my cell phone - have used the guava app http://nosimcard.blogspot.com/ to make a VoIP phone call. I tried this on the edge and it connected and logged me in, I called myself and the Edge rang. I answered, but the Mic and speakers did not kick in. I already sent this info to tech, but if more people are interested maybe it will become a priority.