Yeah, it's hard to get to a specific patch: you can't enter the patch number, you can't sort in ascending or descending order, you can't see more than 50 issues.
Sorry, i don't know any trick. Someone should post a bug in the berlios project's bug tracker.
There might be a page variable to pass along with the url...
EDIT: if you know the name of the patch, then you can search it. That's the only way i know to reach a specific patch.