I've tried avoiding diving into the code of phpbb as much as possible, mostly because I had yet to really learn the syntax for object oriented php, so I don't know much and can't help much.
I hate to just tell you to search for it but since I can't help much (I dunno about anyone else on the forum either...), I can say that stackoverflow.com
is a great place to find solutions to something like this, try there first. There's bound to be someone else with the same question. If not, then you can be the first to ask. I've been lost and searching the web and most of the time I end up on stackoverflow with the coding answer I need.