I assume you're using a "classic" pronto (1000 or 2000) and not one of the next generation remotes. If so, it's likely that Tonto (a third party substitute for Pronto Edit) will work with Com 4. It's much better at communication, and is very similar in programming. It can be downloaded here: [Link: giantlaser.com]
I also think that tech support was giving you alot of bull. Sometimes these folks tell you it's a bad idea just so you won't try something, run into problems, and then call them back. Still, Tonto may be the best approach.