I’m using max 2012sp1.
I have a direct3d material that has tga textures hooked up in the diffuse,spec,norm slots.
With 3dsmax still open, I use photoshop, edit those tga files, then save them out over the already hooked up tga names.
Max does not hotload the textures.
HOWEVER: if I then drop the textures into a standard material or to any material slot and re-save the tgas … the textures in non-direct3d materials will hotload AND thereby hotload the direct3d textures as well.
Anyone have a proper work around? 
I’m going to send something to Autodesk soon – but figured I would see if anyone has already worked out a solution.