Vertex Colours to Flex
Converts the black/white value of an object's verts into weights in a Flex modifier. Thus you can paint you Flex weights using Vertex Paint instead of Flex's default paint interface.
View an Interface Screenshot
copy 'Wahooney Tools - Vertex Colours to Flex.mcr' to your 3dsmaxuimacroscripts directory.
Bind the script to a Key - add it to a toolbar or Quad Menu in CustomizeCustomize User Interface.
**The script can be found in 'Wahooney Tools' category.