For the time being, you can edit the colors in saved costume files and then load them.
CostumePart ""
{
Fx Capes/N_Characters/T9i24_01/CapeFemT9i24_01.fx
Geometry N_Fem_T9i24_01.GEO/GEO_Belt_T9i24_01
Texture1 !X_Belt_T9i24_01
Texture2 none
DisplayName P177456852
RegionName "Upper Body"
BodySetName Tight
Color1 255, 255, 255
Color2 255, 255, 255
Color3 31, 31, 31
Color4 227, 227, 227
}
This is the block for that piece. Colors 3 and 4 are the interior. If you edit them in a costume file, they will be colored correctly when you load it.