[cisco-voip] Secure calls between CUCM and CUCME

[Phil G]

Hi!

Has anyone experience with secure calls between a CUCM-Cluster and a 
CUCME-deployment connected through a gatekeeper?

Security-configuration (CTL-file, CAPFetc.) on CUCM-Cluster is obvious 
for me.
Security-configuration (CTL-file,CAPF etc.) on CUCME is obvious for me.

But are secure calls between CUCM and CUCME possible (i know that secure 
calls between 2 CUCMEs are possible)? In CUCM-Admin we have a 
GK-controlled Intercluster-Trunk pointing to the CUCMEs.

How will the SRTP-keys be exchanged? BTW: How will the SRTP-keys be 
exchanged between 2 CUCMEs?

Another question:

Lets say we have a CUCME configured with security. In CUCME we do not 
have any security tokens, what if we have to replace the CUCME-router, 
how do we sign the CTL-file with the old security "tokens" (which are 2 
SAST-certificates),so that we do not have to delete the old CTL-file 
manually?