Im ay be able to shed some light at this question.
It seems the pics in the Ingame\ directory of the menu zip file arent even parsed. Remove some of them and it still works.
The reason is quite simple, these files are dummies. The real stuff is in the MemeAtlas_0#0.dds files in combination with the tai and tac files. I guess the tai and tac files tell bf2 to internally redirect any calls made for the tga files in the ingame/ directory to the atlas file, to a certain offset with is given in the tai file itself. Mess the atlas files up and youll will definitly see some results.
Heres a pic of a (cheap-ass) silenced G36C:
As you can see i obviously did something wrong with the .dds file, but i made it very quickly to see some results.
The red S (it looks like a 5, i know

) means its the small version. The big ones are in the kit selection menu.
Im gong to see if i can get it fixed, i think i did something wrong whith compression (it looks much uglyer now)
Atleast you have a start for your silenced g36C
Edit:
Seems we need to look more at the bfeditor.gotfrag.com forums, they got it all explained there. You cna use the atlastool provided by dice and create a patch the _00X way.
http://bfeditor.gotfrag.com/forums/view ... sc&start=0