Workaround for the DayZ 1.07 snapping bug: Make sure you select ‘Snapping On’ before you start placing, to prevent all items snapping on the ground level.
Basically, having lock snapping toggled ON, will place the object in the correct snapping orientation, no need to use the mouse wheel, for you lazy people! Turn the button back off if you wish to rotate the hologram.
Each base-building object from BBP has “snapping points”. Snapping points in this mods definition are memory positions that are predefined and set specifically for each model. These points are used to position and lock the hologram of the kit in your hand. You can then rotate with the mouse wheel to correctly snap the hologram object to the base building object you want it snapped to.