If you haven't already noticed, Xfire doesn't seem to do its overlay thing when playing WAR so don't expect any quick replies when you see someone on WAR.
I'm still playing via the Beta Client, as I've not yet bothered my lazy arse to go into town and pick up my collectors edition from HMV. You can manually direct Xfire to the game directory with the executable file in it, that's what I had to do with the beta.
The Beta client is valid up untill the 1st of October or something apparently.