I'm not sure what the technique is -- I've been using an in-house trial of the RMX app and had nothing to sync it with, so I can't say for certain how it will work with the USB S/R.
A quick search resulted in a post on StackOverflow about BPM, so I expect it would be included, or what would be awesome (with the RMX app) is exchange of the rekordbox grid data!