There are 8 rivets that go in the belt, just make sure they have a solid head. They make a rectangular pattern on each side of the TD... have a look on my build thread for the placement. If you can't get enough from there, I can take some more photos of my belt and post them up. Also have a look at the reference that star raider put up, you can see the belt rivets on there too.
As for the holster, I actually an just going to have mine loop around my belt as it is more of a convenience thing for trooping because I don't think the actual character model has a holster.