When using custom init/start/stop messages, no command word or default params are sent over. This results in loosing part of the call information which is unavailable to the AVP set, such as dialogid.
Also the issue for the format, for default messages, a certain format is used, custom, completely different. It seems like these custom messages were overlooked in the original code perhaps because no one used them. Attached is the patch that corrects this behavior. Custom AVP's should be IN ADDITION to the standard message AND in the SAME FORMAT, without loosing dialogid.
Below is an example of a default start message and then a custom one before the patch.
Default START MESSAGE example:
Custom START MESSAGE example (BEFORE PATCH):
from = sip:firstname.lastname@example.org to = sip:email@example.com callid = 9xNQjtR8M7Q1jI8U960DPvVXWgBoyzNt
Custom START MESSAGE example (AFTER PATCH):