How can I use the dualforward parameter in my unity shader to use lightmaps and normal maps together?

Question

I'm using the free version of unity and I would like to combine lightmaps with specularity and normal maps. After doing a -bunch- of research, I've figured out that there doesn't seem to be any easy way to do this in the free version of unity, which doesn't support deferred rendering/easy use of dual lightmaps.

However, it looks like it's possible, by writing a custom shader, using the "dualforward" parameter in a shader, switching the lightmapping mode to "dual lightmaps" and turning on "Use in forward ren." (basically, writing a shader that specifies the use of dual lightmaps, which should allow for a combination of lightmaps and normal maps)

So I downloaded the source code for the default shaders (because all I need is a normal specular bumped shader) and added "dualforward" to the parameters:

Shader "Bumped Specular Dual Lightmaps" {
Properties {
    _Color ("Main Color", Color) = (1,1,1,1)
    _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1)
    _Shininess ("Shininess", Range (0.03, 1)) = 0.078125
    _MainTex ("Base (RGB) Gloss (A)", 2D) = "white" {}
    _BumpMap ("Normalmap", 2D) = "bump" {}
}
SubShader { 
    Tags { "RenderType"="Opaque" }
    LOD 400

CGPROGRAM
#pragma surface surf BlinnPhong dualforward

sampler2D _MainTex;
sampler2D _BumpMap;
fixed4 _Color;
half _Shininess;

struct Input {
    float2 uv_MainTex;
    float2 uv_BumpMap;
};

void surf (Input IN, inout SurfaceOutput o) {
    fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
    o.Albedo = tex.rgb * _Color.rgb;
    o.Gloss = tex.a;
    o.Alpha = tex.a * _Color.a;
    o.Specular = _Shininess;
    o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
}
ENDCG
}

FallBack "Specular"
}

This, however, doesn't seem to work. When I keep the "dualforward" param, every object that uses it seems to be lit by the one directional light in the scene. When I remove the "dualforward" param, it they look like normal lightmapped objects with no normal maps or specularity.

I noticed that the support for "dualforward" seems to be new in v.3.4.2, so I made sure to download it (I was running 3.4.1), but it still doesn't work.

Anybody have any advice for me?