Let's try these few softphone to connect to Brekeke SIP server.

Kapanga
http://wiki.brekeke.com/wiki/Interoperability:SIP_Phones:Soft_Phones:Kapanga

Xlite
http://wiki.brekeke.com/wiki/Interoperability:SIP_Phones:Soft_Phones:X-Lite

AGEphone
http://www.ageet.com/files/AGEphone2-Setup.exe