Replace Color Generator Clips in Atem mini generated Project

Hi,

I have an BlackMagic Atem mini extreme ISO and had recorded a few videos with multiple cams. I also used some transitions and super source things.

As I read some days ago super source and non standard transitions are saved in the drp-file as black color generator parts

So how can I replace all those black clips with a single video or a composite clip where I try to reproduce the super source effect or a single video without losing the transitions.
Timecode is already present in all ISO videos, so this should not be a problem to get the right areas of the videos.
Replace clip won't work with the generator clips. I tried that a few days ago in Davinci Resolve 18.6.

Any tips would be appreciated

Marco W.