I don't think the MSG card is required.

UCD is a little flaky to set up because of the way all the timers in Class 4 interact with things. You need to make sure you have an overflow time set at the very least or the call will never overflow anywhere. It will only overflow to another hunt/UCD group. IIRC software version 8.x made provisions for voicemail to connect with UCD groups as it added a field in VM packet integration fields.

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.