we have an internal DID range 6XX in our company and we are going out of the CUCM cluster through a H.323 gateway which is a ITSP's gateway (NetCentrex platform I believe). Recently we upgraded to 220.127.116.1100-9 CUCM and since then have trouble with call forwarding and ANI representation to the ITSP. The problem is that when you forwarding an outside call to an another outside destination CUCM collects the ANI number of the original (outside) calling party and since we have a DID range and our respective side ID the calls get dropped because of the wrong ANI number. So basically we need the ANI number format when the call is forwarded outside: Site ID+our internal DID range. We have a route pattern through which we go out and we set a prefix range (our site ID) in front of our DID range and that works fine. We set the Call Routing Information - Outbound Calls/Calling Party Selection on the H.323 setup page to the "First Redirect Number" so that the CUCM sends our DID range and not the ANI of the outside calling party when the CFA is used. Site ID prefixing on the router pattern works fine but the problem happens when somebody inside the cluster sets CFA to an external number on the PSTN. CUCM seems to ignore the prefix digit parameter on the route pattern through which the call goes through and sends only the DID range without of the prefix SiteID in front of it and the calls get dropped. We also tried the Call Routing Information - Outbound Calls/Caller ID DN on the H.323 gateway setup pages and set "SiteID"XXX pattern to try to force the correct ANI number presentation but the same things happens. Why are number transformations not working when it comes to call forwarding on CUCM?