Obviously you've found a solution already but I just wanted to add one thing.
Opera has an ini file somewhere that you can put adblock patterns into (or at least it did when I tried it out in the 7.x days). I just copied my firefox adblock patterns in and it worked fine, although I never had expressions more complicated than * matching. Incidentally, the difficulty of doing this (edit text file, restart browser as compared to right-click and block in firefox) is one of the big things that kept me from sticking with Opera for longer than a week.
Anyways, not sure where to find details anymore but I originally stumbled on them by googling "opera adblock".