.bypostauthor attribution lost after XML import

I recently had to reinstall my blog, and I only had an .XML-file as a backup. The comments made by me, the author, used to have a different style (the .bypostauthor class) so that other users could easily identify me.

The problem is that after the XML import, this distinction must have gotten lost – I’m obviously using the same style sheet, but my comments now look like those of a regular user.

So my question would be, is there any way that I could re-assign my comments to that of the post author?

Any help would be appreciated greatly!