Small issue with labels & rules

As moderator I get dialy 10 pm's or more. So I like to keep them organised. So, I use labels.I think that this is a glitch in the forum code but when the username has a space I can't make a rule for their pm's.
I tried to make a rule that when John 591 pm'ed me that it directly gets a label of moderation, because he mainly contacts me for the NDS section.
But try it and you will see that it is impossible, because you haven't select a criteria or an action.Do anyone have an idea to solve this?

Why don't you use underscore?i.e. John_591

Does that work?

I dunno, try it.

Nope

I wasn't even aware smf had this feature... Will see if I can find a bug report at the smf forums.