Anyway, PrpShop for Windows can be downloaded from here. Look for the "PlasmaShop 3 BETA installer", it's bundled with it (up until now I used version 233, I just upgraded to version 237. Both work fine). Also, the topic here on the GoW is this one (in case you need a Linux version or some other tools. But with PlasmaShop and PRPShop you can do mostly anything).
(now that I think about it, it's one of those cases where my instructions aren't really clear, since I only mention to download PlasmaShop without giving a link or anything. My bad.)
Cskid: just checked, the latest version should allow you to replace textures, but it seems limited to the DDS format. However there are some good converters on the net, you should have no trouble finding one using google (I'm using Gimp with a DDS plugin, which works fine).
Then you just need to double-click a mipmap, and select "Import DDS".
Anyway. My apologies if my previous post was aggressive. I was a bit irritated because I spend two hours unsuccessfully trying to mix textures in Korman and they simply refused to show up correctly in Uru. (Anyone who tried making a material using more than two textures for Plasma probably knows what I'm talking about
)
