SIP softphone with CME

Dear All,

I was trying to use Cisco IP communicator as a SIP softphone with CME. It looks like, IPC works only on SKINNY protocol even though SIP is configured on CME.
other issue is that, I configured IP phone (7941) but wireshark is not capturing any data.
I referred the doc (https://supportforums.cisco.com/docs/DOC-11735) but no luck.

can any one suggest what is wrong with this.

I wanted to integrate a SIP softphone which supports G.711 and G.729 on CME. can any one please suggest any free soft phone which supports this..