Nested categories

Thank you for this great plugin. I’m using the free version for a non profit photocommunity.

Is there any way to output nested categories in a nested ul list on the categories page?

like:

outdoor event
— foto walk
— portrait shooting

indoor event
— portrait shoouting
— fashion shooting
— architecture shooting

Currently they all show up in one non-structured ul list.
This is not a problem (only a luxury problem)