how to handle depth for 2-sided

If i set double sided face culling, there is no depth for back face. Unity use the 'ShadowCaster' pass as the depth pass, but Shader Forge can't write 'Cull Off' to the 'ShadowCaster' Pass.
when using Opaque shaders, I can use a common custom Fallback shader with a 'Cull Off' ShadowCaster Pass. but If using Cutout shaders, the situation will become complex.

How should i solve this problem, Please help me.

Maybe Shader Forge should write 'Cull Off' into the 'subshader block' ,instead of in every pass, and generate a 'ShadowCaster' pass for Opaque.