I've reading the forums for a couple of months now, and I've found a lot of useful tips. Finally, I can express my gratitude, cause I'm sure my tip can help many people. I've found this nice sdk a few weeks ago, and I can do a lot of things with it (for example: webphone, voice recognition application...).
Great news, it can be connected to the Cisco Unified Communications Manager. If you want to try it, you're able, cause there are many great sample programs on this site: Ozeki C# VoIP SDK - How to setup Ozeki VoIP SIP SDK with Cisco Unified Communications Manager
Let me know if I can help you with anything!
Have a nice day!