How Can I Bake ShadowMap With Front-Culling?

What I want to do is to use lightmass to bake lightmap. I have noticed that there is a shadowmap input.
I think I can change ShadowMap’s rendering pass as front-culling (not backface-culling), but how can I do it?
Tradissional material use two-sided does not use( because it does not cast any shadow )