I feel like an idiot - how do I use this darn dagger frog?

I nabbed a couple of www.museumreplicas.com/p-131-leather-dagger-back-hanger-frog.aspx these dagger frogs from MRL a couple weeks ago when they were on the deal of the day, just to see how they worked. Well, after much screwing around and trial-and-error, I've come to the conclusion that I have no idea how this piece of leather with buckles on the corners is supposed to support a dagger.

Other frogs I've seen look pretty self-explanitory, but this one, for some reason, is not. I've tried putting the dagger sheath through the buckles in various orientations, tried wrapping the frog around the sheath, again in several orientations, tried rotating the buckles and straps to inter-connect them in every way I could think of, and in all cases, the dagger ends up in some strange and awkward position when hung on a belt or just plain falls out because the frog can't grip it, usually both.

So if anyone has a dummy's guide to frogs handy and could help me figure this out, I'd appreciate it. Better yet, if you have this particular frog and can show me how it is supposed to be used (or tell me that it's crap and doesn't work), that would help too.