I've begun to build mine back into HLSL (so far so good, *crosses fingers*), here's how I manage the two passes:
Code:

---

technique normalMapping
{
   pass EnvLight
   {
      //globals
      zwriteenable= true;
      zenable = true;

      //shaders
      VertexShader = compile vs_1_1 vs_main();
      PixelShader = compile ps_1_4 ps_main();
   }
   pass DynLight
   {
      //globals
      zwriteenable= true;
      zenable = true;
      Lighting=True;
      AlphaBlendEnable=True;  
			
      SrcBlend=One;
      DestBlend=InvSrcColor;

      BlendOp=Add;

      //locals
      ColorOp[0]=SelectArg1;
      ColorArg1[0]=Texture;
			  
      Alphaop[0]=SelectArg1;
      AlphaArg1[0]=Texture;

      //shaders
      VertexShader = compile vs_1_1 vs_main2();
      PixelShader = compile ps_1_4 ps_main2();
   }

}

---

vs_main2() and ps_main2() omit the base texture and only render the lighting pass; it is rendered with alpha blending over the other pass, illuminating the texture from it.

Of course, there are also advantages to keeping both lights in a single pass, as you can condense the shader more and not worry about going overkill :P.

-Rhuarc