L4d2 skin porting

Hello folks, I am having trouble getting sounds and some particular range of animations to work in l4d2, as well as having trouble trying to find out how to flip cs:s skins or original models for use in 3dsmax. Someone told me this isn’t necessarily the wrong place to ask questions for, since it’s related to porting and source engine games, so I thought I’d ask here even if my problem is not gmod related.
Here is what the sound and animation problem looks like: http://www.youtube.com/watch?v=fbbSMPROGaE
I don’t really know how the blending between the running and idle animation works, so I just thought I’d constrain the idle animation in it’s original pose to the l4d2 running animation and see if that works, but it doesn’t as you can see. The sounds… I don’t know about that, they’re just completely distorted in comparison to what they actually sound like and I don’t know what to do about it or in which kind of format to convert them to. Lastly the viewmodels - I tried mirroring cs:s models and bones to see if that would solve the problem, but the smoothing of the reference mesh is lost when applying the modifier. Can anyone help me out? I’ll be honest now, I didn’t do 5 hour google researches on these subjects, but that is because I’m getting tired of it.