How do I create an animation channel for my track section?

I want to create my own channel for variables of a certain type and give them special interpolation logic. I created my track and added a section to it, they are displayed in the sequencer:

But for a long time I can’t figure out how to add a channel to this section, I’m trying to add UMovieSceneFloatChannel for test

This is what my section looks like:

I made classes for the track and section according to this guide: UE4 Sequencer with custom tracks
for which many thanks to its author

How can I display a float track in my section? Does it need to be registered somewhere similar to tracks?

I can provide the rest of my code