Yeah, so if you're on release 7, SM can strip all Avaya headers on an adaptation out a SIP trunk.
If the Patton is UDP only (and you'd have to specify TCP or UDP explicitly on the ATA) and you do it as a trunk, then you can maybe work it in UDP as a trunk.
SM also has something called implicit user rules where you can map incoming SIP trunk traffic to a CM user through application sequencing like you would a SIP phone. The idea being that you could take a Norstar for example with PRI and Nortel digital phones, send CLID on that PRI to a SIP gateway to SM to CM and have calls process through CM according to station routing with COR/COS/etc. The Patton could easily do the same. I wouldn't recommend it!
It sounds like a monumental pain vs Audiocodes MP112's that can be had very cheaply.