A format that supports backgrounds?

I've got this DVD with hardcoded subs. But I also have a subrip in another language that I'd like to use for my XviD encode. Thing is it looks a bit garbled when the subrip comes on top of the hardcoded subs, so I thought I'd add a background just to cover my text (you know, like the CSS formating on webpages) over the text. Is there any format that supports this, and if so, howe do I do this? I've got a simple *.srt (which could of course be converted into any format).

If you convert it to SSA format, that allows you to set a solid box behind the subs, like closed captions.

Yes, in the style section of the file, you need to set the borderstyle to 3.

Ah, ok :) Gonna try that. Thanks! :)