Select a edge of the brush (e.g in the 4 window view) - go into the brush edit mode - click onto split - now you should have some extra vertices 
But I would recommend you to do that in your 3d program ^^
Select a edge of the brush (e.g in the 4 window view) - go into the brush edit mode - click onto split - now you should have some extra vertices But I would recommend you to do that in your 3d program ^^