Changed help message with control keys in sip_audio_session

darcs-hash:20090114181021-1e3d8-e670c1d0b0ef0714c378e80947fca3751b3f0c50
removed unused arg

darcs-hash:20090115103417-b2873-ac0552a6a0eb82cc4d975077d00f0b9f4aa3fb9a