NV register combiers into standard OpenGL?

I have a rendering system for the main characters in the game with effectivly five textures.
-specular map
-team coloured enhancements
-team coloured enhancements

I render diffuse lighting first pass (lighting+glow+specular*spec) and then multiply the 2nd standard colour (base with team textures A and B alpha alpha blended with it) pass with it.

Can I get this to work on the old ATI Radeons with three TMUs and other low end cards with 3+ TMUs? (SiS Xabre, Trident XP4, ST Micro Kyro, Intel 845G)

What about for cards with just one or two TMUs? Normally the equation is sort of first pixel=(diffuse+emissive+specspecmap) and then finalpixel = first pixel(a|b|c). I have to change the equation, don’t I?

I think GL_ATI_texture_env_combine3 might help you for the old Radeon.