The detail color has a value of 12 (0x0C). Our tools can not go higher than 8 (0x08). I already knew that this existed since the release of BFME but thanks to MaDDoX I found out this week what the actuall meaning of this value is: Housecolor.
I made an app to do it but somehow broke it when making the UI. I should have some spare time this weekend to fix it.
Edit:
This should do it (although I also said that yesterday to MaDDoX
http://www.makaveli.nl/rene/BFMEHouseColorer.exe
It's a really simple app. After lauch press browse to select the w3d file to edit. A list of all meshes in this file appears. Select the ones that should be housecolor. Press update and the shader for the selected meshes is changed.
Current limitations are that the housecolor mesh should not contain a multimaterial nor should it contain a multipass material but I don't think that should be a problem.
Edit2"
Due to the fact that the number of actions required for this is very limited it may appear that nothing happens, this is not true though.