can't follow.
I can't call the sublayout of the edit-page.
There must be a possibility to call it by a menu-item with a new entry in the menu-item-manager.
For exmple:
I created an alternative layout for article-editing at com_content by copying and renamig the template-file of com_content/views/form/ to the template-folder with a specific name.
edit.php --> something.php
edit.xml --> something.xml
Then doing some changes at the XML-file.
...and so I got a new selection for content-edit with my special layout in menu-item-manager.
All I want to do ist the same with the JEvents icalevent.edit-page
But don't know how to do that.