http://blogs.msdn.com/cenet/archive/2008/05/13/inspect-incoming-sip-headers-in-rtc-ce-6-0-r2-release.aspxThere are many scenarios where inspecting incoming SIP messages for custom headers is useful. Many servers add their custom headers for custom functionalities like custom ring tones, shared line functionality, privacy, etc. and hence having the abilityen-USCommunityServer 2.1 SP1 (Build: 61025.2)