I've got an MTX Explorer 29er. You can kind of see how it's mounted here (hi-res pic of the bike, don't want to pollute this thread).

Mine was definitely a PITA to mount because my frame looks like this at the eyelets:



I had to do this to the extenders:



Something to watch out for...when you pull an MTX trunk bag off of the rack, it's easy to break your tail light. I broke a PDW Radbot this way. It was mounted with a PB tail light rack bracket. I just switched over to the universal clip bracket that came with the rack. That puts the light a little lower, so I'm hoping for the best.