Max will not display vertex colors in the viewport by default. You have to force it, in Object Properties, via Vertex Channel Display. Or you can use a DirectX shader that supports vertex color.
yeah most of the time i'm not able to assign the vertex color from the diffuse either. Sometimes it weirdly works after checking/unchecking some options but as i'm not considering myself as a max noob, my bet is : it's pretty buggy.
so good news for you Noors this works 100% sure, just second before I decided to script it myself google revealed this to me.. I'm pretty happy cause for time it will be crucial part of my workflow..
Replies
CREDIT
or
object properties > display vertex colors
@nezach: anyway this script works... max assign vertex colors don't.. so who wins? :P
http://www.renderhjs.net/textools/
You get no diffuse colors to the vertices from using it at all? It works for me so I guess I 'win' at that. /shrug