Off-screen viewmodel

Ok, so I'm trying to take a custom weapon from Counter-Strike source (with permission, of course) and place it in the Spy's capable hands as a revolver skin. I actually managed to re-skin my custom weapon over the revolver viewmodel, then removed the original. Everything moves like it should, only... when I go in-game it's so off-center it's not even on the screen! :O

Using MDLDecompiler and 3DS Max with the SMD import/export plugins, I don't know what else information might be needed.

Bit of an update:
I'm using an existing TF2 skin (the Deagle) as reference. Getting the positioning right and so on.
If I drop this as-is into my models folder it works perfectly in-game, as it should. However, when I recompile it just to test, mdldecompiler -> studiomdl, having made no changes whatsoever it's seriously screwed. When I view the reference model in 3DS everything looks great until I test it with animations, then one of the arms is completely broken and not where it should be.

Er... what does Valve use to edit models and compile anyway?

Ok, turns out I just needed to rotate the anims 90 degrees. xD

I've got the viewmodels, world model and even some custom sounds made, but something strange is happening. The RED version of my skin is perfect, but BLU's has some weird black texture spots on it. Also, are there any good tuts on making a weapon cloak?