Redownloading past themes you've paid for

[Chromama]

I've purchased a ton of child themes from the very wonderful guys here at Studiopress (seriously won't go anywhere else) but along the way must have deleted a couple of the zip files (I keep the originals in case I decide to change my mind or want to use them again for a different blog down the track)...

My question is, is there a way you can re-download previously purchased child themes (after first proving that you have, in fact, paid for them already)? I know you can do it for the Genesis framework on it's own (I have it running on three blogs at the moment) but what about the child themes?

Cheers,
Karen