Registration form from Events Manager Pro

Hi,
I need to edit the registration form in Events Manager Pro plugin. That’s OK. But I would like to use LWA for registration, but I can’t see there the fields from Events Manager. I am using their tool Forms Editor.

…when I use for editing registration form any different plugin, it works. (WP Members, Theme My Login, etc..) Why not with EM?

Is there any way how to connect those two? Thanks for any advice!
Tomas