[Pro Sites] How to override ProSite front page like Registration.php ?

Hello.
We try to override the front pages of WPMUDEV plugins like Prosites.

Example:
We try to override Registration.php so we duplicate pro-sites/pro-sites-files/.../.../Front/Registration.php and create folder in our theme (like um-member or Woocommerce works) but we can't.
So How to override ProSite front page like Registration.php ?
Thx to your help.