I've got the solution. Only my second post on here, but I've been browsing for a while. Open up any stock paa file. You'll see 4 boxes. The top two should say RGB or something like that. The bottom two should say DXT1, maybe DXT3. That's a .DDS format. Save your retextures as .DDS with DXT1 format and then open them in TexView2. Then, save as .PAA. Yes, I've tested it, done it a bunch, and it works.