Ok, did some playing around on the Oracle side and answered my own question. Will post here in case anyone else is interested.
Took the function code in the package and made it an independent function. Transaction Group still couldn’t find it.
Took the function code, removed all the Return statements and made it an independent “procedure”. Transaction Group found it and it worked fine.
Took the new “procedure” and placed it into the original package I was working with. Transaction Group found it and it worked fine.
So I learned that Transaction Groups can’t call an Oracle Function, even though the only difference I can see is that a Function has to have a “Return” value. Otherwise both Procedures and Functions both have input and output parameters and seem to operate the same.
Also, you CAN call an Oracle Function using the system.db.createSProcCall, which is a decent workaround unless you want to use the built-in store and forward functionality, of which I guess I can roll my own solution for that.
Thanks!