Tatonka 75+10 Bison fitting rifle scabbard

Hi guys an gals
Just purchased a Tatonka Bison pack and got the scabbard to go with it. Problem is.............. no one, and i mean no one knows how these should be fitted properly. Been back to place of purchase, given lots of options, none of which seem appropriate, none of which seem to be accurate or look right......... even been to other outlets........ sales people give ideas, but no one seems to have it nailed. Tried getting in touch with Tatonka, but nothing has arrived.
So question goes begging......... does anyone on here know the correct method of attaching scabbard to pack? The buckles and length dont seem to be aligned to match anything on the pack......... pics would be awesome ta
Cheers in advance.