Officially: That's one of the problems Matt and I have discussed - you don't. With the current UI/functionality they will always be unidentified and you'll need to browse files to see/reach them.

Unofficially: If you're using Boxee on a computer system, you can use a third-party program to manipulate Boxee's DB and create or modify entries. There should be numerous discussions in the Boxee forums about a few ways to do this.