Single-pass stereo with command buffers

I have huge problems rendering my own geometry shader stuff with single-pass stereo enabled. I'm using CommandBuffer.DrawProcedural to render the object during CameraEvent.AfterGBuffer, but the rendered geometry is displayed only on one eye, or not at all. Apparently there's something special I should do within the vs/gs/fs, but it's a bit unclear what that would be.

I'm using the Unity's macros in the shader (like unity_MatrixVP, which has separate macros for stereo rendering) but it...

Single-pass stereo with command buffers