Hi Metin, there is a new option in V4 for exporting vertex colors to FBX format. You need to enable it in moi.ini under:

[FBX Export]
WriteVertexColors=y

Also to get an FBX file from MoI to Blender you'll need to modify the version of FBX file that MoI exports, see here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=8683.9

- Michael