Sip register and audio call

I'm looking for a developer to develop an android library in order to make a sip voice call (outgoing calls only) . Most important functionallities : 1) register 2) make outgoing call to the server 3) check if call established 4) check if registered 5) end call 6) un register I would like to have these all back functions : 1) onRegisteration failed / success 2) onMakingAudioCall failed / success 3) onEndingCall failed/ success 4) onUnregistering failed/ success Now the most important part, not to use the android sip api, cause alot of phones block it. I need a working test application. Can be based on mjSip too.