Need to extend trap fitting

I replaced a rust clogged vent and drain pipe with ABS. Rather than patch the old plaster wall which I originally planned to do, I put 1/2 new drywall over it. Well, now my nicely cemented trap fitting sits partially inside the new drywall. Can these be extended with a threaded fitting, and if so, would this be any code violation? I live in PA. I'd sure hate to rip the drywall off after all the trouble I went to. One to learn on, I guess.

Rowdy Roddy Piper... Now thats a blast from the past!
Still wearing the kilt and doing an occaisional body slam?



I wouldn't trust the threaded connection.
I'd drill it out of the tee with a rambit.
Then I'd put in a short length of pipe and extend it out with a new slip joint adapter glued on.

problem

The trap adapter thread is too fragile for an extension, and it has a straight thread which will not tighten to anything except a slip nut.