I think that only marshall Tito wore visor cap in late war,but thats not the case here
Im not sure,how much effort and modding(i have no idea what you can do in the editor) you're willing to put in this,ill try to represent a partisan side,considering that they fought on german occupied ground in 44'
They wore what they could get their hands on,with different combinations,just avoid camo uniforms and enemy insignia on them,because they were really rare. Equipment was simple,mostly german,a lot of them used prewaryugo belts(very similar to russian one),german pouches for ammo,simple backpacks,no shovels,bayonets,here Ill give you couple examples:
http://www.shrani.si/?33/6U/4BtHkehc/img136.jpg
http://postimage.org/image/59zymnmtg/
http://postimage.org/image/5a0vpekp0/
http://www.shrani.si/f/36/AV/1F8BTTrS/70fb69a324d44c24a7ff5b89.jpg
http://www.shrani.si/f/b/tz/3EfbbykD/96b7bb662c8c4117b3fa9d7a.jpg
http://www.shrani.si/?q/Kv/4hrvJ0t8/img153.jpg
Weapons:
There were quite a lot of rifles,mostly mausers(german/pre-war yugo),couple of lee enfields and mosins here and there.
As for smgs,you can really play around,mp40 was common so was ppsh 41,little less mp 41 and mp 28 since police and ndh army used them,also sten from british aid.
MGs:
With bren and vz. 26,both german mgs were really common
Grenades:
Anything that goes *boom*,you cant go wrong here,but i would suggest to use russian f1,they used them and they are similiar to prewaryugo bombs
Pistols:
Only officers and m.gunners had them,personal choice really,but p08,p38 and TT33 were most common
Oh and cockades,came from russia late 44' in the begining only officers wore them,most of the fighters had red star sewn on their cap.
This is it i think