PixelDepthOffset on other Kite tree models and in Speedtree

Hi,

I believe the title says it all. Right now only one birch supports pixel depth. The others look like this:

https://i.imgur.com/FHIZgzFm.png

I tried to copy the material M_CustomDepth, which is kinda weird b/c it does not plug anything to custom depth in the end, only to notice that I needed custom depth billboards texture which other trees did not have. Is there a way to generate them for those tree? And for newly created speedtree models? Thanks