Don't have a clue about how to get V4 into Blender for painting, I don't use Blender. You'll probably have to reapply any image maps, in elaboration also not sure how Blender deals with .mtl files if applicable, and your import method (from Geometries?). A lot of unknowns...

Maybe forum member vilters can help, although he seems to have an allergic reaction to V4 and her UVs layout. Still...

Found this_

http://sickleyield.deviantart.com/journal/Tutorial-Seamless-Texture-Painting-In-Blender-439338827

Looks like it's coming from a DS perspective but maybe something useful for starters?