Yes, ventilator is right.
This is the default render setting used by the engine:
Models, sprites, and flat textures:
SetTexture(0,Skin);
SetTextureStageState(0,D3DTSS_COLOROP,D3DTOP_MODULATE2X);
SetTextureStageState(0,D3DTSS_COLORARG1,D3DTA_TEXTURE); // entity texture
SetTextureStageState(0,D3DTSS_COLORARG2,D3DTA_DIFFUSE); // lighting
Shaded textures:
Stage 0 adds dynamic lights to the lightmap:
SetTexture(0,LightMap);
SetTextureStageState(0,D3DTSS_COLOROP,D3DTOP_ADD);
SetTextureStageState(0,D3DTSS_COLORARG1,D3DTA_TEXTURE); // lightmap
SetTextureStageState(0,D3DTSS_COLORARG2,D3DTA_DIFFUSE); // lighting
Stage 1 modulates the actual texture with the result of stage 0:
SetTexture(1,Texture);
SetTextureStageState(1,D3DTSS_COLOROP,D3DTOP_MODULATE2X);
SetTextureStageState(1,D3DTSS_COLORARG1,D3DTA_TEXTURE); // texture
SetTextureStageState(0,D3DTSS_COLORARG2,D3DTA_CURRENT); // stage 0
The shader must emulate this setting.