I've never needed this white and black information before. I played around for a few minutes, and I wasn't able to get this information from Arena, either. I suspect you can't.
Probably the easiest solution would be to install Scid vs. PC, then load the PGN database into that program. Scroll through the games until the player you're interested in shows up in a game. Then click on "Tools --> Player Information", and pick either White or Black, as applicable.
http://scidvspc.sourceforge.net/index.html
In Arena 3.5.1, how can you view the results of a CPU tournament broken down by how each player performed as *white* and *black* ?