Hey womble,
Heres how you do it, as for doing it for mac. Obviously mac always had the bad end of mod making so you have very little options. You may only do porting/converting for rvs. ut2003 supports no editing software.
Map's envolve program like studio max 3d or any other 3d rendering software. None of these editors are avalible for mac. So when u convert a map. First download it, install it, then you will have a couple folders. The main folders that i want you to look at is the "textures" and "map." Almost all maps made over on the pc side were done on v.1.5 or 300 something. Our version is 294. So you will have .rsm/.utx errors unless to convert the game versions. A simple program called, "Build Manager" can do this. Once done, pack it up and send it to a mod distrubitor AKA, spark or monoman. Get your mod out there!
Weapons/skins involve a program called SDK. Stands for Software Devoloper Kit. Ubi Soft has yet to released it therefore it is unbelievable hard to make basic skins. So far i only spoted one clan to "claim" to figure it out yet showno proof. So simpily, it cannot be done.
If you need more help PM me on gr, Account "mainman" or vist our mac help forums @
www.ravenshieldmod.com.
-Mainman