Switch Input Filters

When creating an HTML ad, the default input filter (Filtered HTML, in this case) is used, and all of the

tags are filtered out of the markup. As far as I can tell, there is no way to select a different input filter for HTML ads. I think the best way to implement this would be to ad an input filter element to the form for each HTML ad, then store that value in the database on a per-ad basis. I can write a patch if people think this is the best way to go. Otherwise, could someone tell me how to avoid this problem? Thanks.