[Users] Changing TM Retransmission Count?

Reading through the documentation for the TM module (1.1.0) i've been unable to find anything indicating that i can change the retransmission count, only the retransmission intervals By my count OpenSER is retransmitting an INVITE to an endpoint user 12 times and i would like to reduce this as it is interfering with the call forward no answer logic i've put in place (timer doesn't hit until all 12 retransmissions are sent, which is about 42 seconds using the default timers) Do i have any options other than modifying the tm module code? If so, could someone give me a pointer where i need to look (i've had a quick read and its rather complicated so i might take me some time to find the logic i'm looking for) tavis