I have all the tools for it (Maya 2012, tom xanim exporter and lime) but I do not know how to do it. Can anyone tell me a step by step guide on how to port these weapons? I could'nt find any videos on it either.

You need another program called Lemon to get the anims extracted, but right now it only has support for mw2/bo2, so you cant get mw3 guns yet unless you want to animate them yourself. Get lemon from tom-bmxs website and here is the tutorial to do it: http://ugx-mods.com/forum/index.php?topic=3692.0. Note: watch with annotations on because you need to select different joints for mw2 guns then you do for bo2 guns.

Here's a video for you:

https://www.youtube.com/watch?v=pFTWzHmVT2w

It's an easy to follow tutorial on how to port. You have to extract the .tanims with Lemon and the .ma model files with Lime.

Hey

These two video= Your Gun full workly. But thats only for BO2 guns (vid from Rollonmath)

Thats another vid for BO2 guns from Elfenlied: https://www.youtube.com/watch?v=kN1XZvd669M

But for MW2 ask DidUknowiPwn

MrDunlop4

https://www.youtube.com/watch?v=UCh7DeE70Yo

This is from start to finish, includes models, anims, sounds, and soundalias.
You can follow this video entirely for any game really, but only thing is for anims you have to just use tag_torso instead of tag_view on 3arc weapons.

Hey

These two video= Your Gun full workly. But thats only for BO2 guns (vid from Rollonmath)

Thats another vid for BO2 guns from Elfenlied: https://www.youtube.com/watch?v=kN1XZvd669M

But for MW2 ask DidUknowiPwn

MrDunlop4

Those 2 videos can work for any cod gun but like didyouknowipwn said you need to select different joints for infinity ward guns then you do for treyarch guns, which rollonmaths video has annotations at the part to let you know what joints to select.