http://blogs.msdn.com/cenet/archive/2008/05/13/adding-custom-sip-headers-using-rtc-in-ce-6-0-r2-release.aspxAdding custom SIP headers using RTC, in CE 6.0 R2 release. In CE 6.0 R2, RTC now supports the capability of adding custom headers to outgoing REQUEST messages, for RTC sessions and RTC subscriptions. Here is how once can do it. After CE 6.0 R2 release,en-USCommunityServer 2.1 SP1 (Build: 61025.2)