Importing a 3dsmax animation into SFM

So I created an animation for the Pyro in 3dsmax. In the program itself it works perfecly well, but when I import it to the HWM model of the Pyro it flips him upside down (see screenshot). What’s causing this? I converted the file with “fbx2dmx.exe -nop4 -a”.

https://dl.dropboxusercontent.com/u/79660/pyroupsidedown.jpg

What I have to add is that I have an additional custom item in the file with two custom bones, but I guess it shouldnt be a problem…?
Also: when I import my custom model (that I compiled through the ingame importer) it only shows the bones of the item, not the actual item itself. Any ideas what’s causing that?

It’s very difficult to find information about creating animations for the workshop, so hopefully I’m looking in the right direction.

Thanks in advance!