Rigging Questions for Source models in Maya 2014

Hi, I’m using Maya and have ripped a game model with textures but I have some questions before I rig. First, I don’t know how to get the valvebiped into maya. Second, my model is a human whose proportions are different from the valvebiped. Is there a way I can extend bicep bones and resize all of this to fit the model I have? He would have extra joints as well because he has shoulder guards which should move seperate. I’d rather not create a skeleton from scratch, but if need be, then I’ll do that, but a link to a tutorial would be greatly appreciated. I’ve searched the internet and I’m having no luck finding tutorials for what I want to do. I’m sure they’re there, but I guess I just don’t know what keywords to search for.

EDIT:

I’m still working on getting my model into garrys mod so I can’t verify how up to date this tutorial is, but so far this seems the most useful for anyone else interested:

http://forum.facepunch.com/showthread.php?t=1412147

I ended up abandoning importing from Maya because my maya is x64 so essentials steps wouldn’t work. It seems that 3DS Max 2012 is the popular version for gmodders?

http://facepunch.com/forumdisplay.php?f=40

yes, I understand that the model thread is most likely where I will find the information but I’m having a hard time finding any tutorials in there. I don’t know why I’m having such a hard time finding this information…