We have CUCM 9.1 connected internally to Mitel (MCD 6.0) via SIP. Transferred calls between the two systems don't display the correct caller ID on Mitel sets. This is because Mitel uses the FROM field in UPDATE messages for caller ID on sets display. CUCM never changes the FROM field. It is always the originating name and number. Wondering if a SIP Normalization script can be written to change the FROM field in UPDATE messages to match the RPID and or PAI caller ID info.