We are in the process of having a new 3rd party VM system installed. System is online and we are able to cover to it. our CM is a 6.0.1 and have SIP (TLS) trunks to ASM and the VM system is an entity link of ASM via SIP (TCP). Our phones are 9630 H.323. We are able to cover to a test mailbox, but the MWI is not working. Seems like it is failing when it hits CM on the comeback with 501 not implemented. Any clues on what can be missing in CM.. the station is set as SIP-ADJ on page 2 to match the HG.