How to modify depth blended shader for second camera/reflection projection?

Hey, i'm using depth blended shader as water surface shader (for the edge blending), and i'm trying to render it as reflection (using second camera and code based on Unity MirrorReflection4 script, basically doing inverted culling and custom projection matrix).

It works fine in main camera, however no matter what i do - the depth blending fails in reflected space/texture. I'm using shader replacements for other camera, and i'm feeding custom depth buffer sampler to the surface shader (instead of using _CameraDepthBuffer), but it still doesn't work.

Do i need to multiply some matrices? Feed custom clipping space position?