Make a Document editable on Mobile Client

A MetaProperty must be made editable,not only to get them displayed on the client but also be able to edit.

1. Create a new a Document MetaClass derived from the System MetaClass "FILEDOCUMENT
2. Create a MetaProperty of type "Boolean" with the Name "EDIT_FILE_ALLOWED"
3. Navigate to the MetaClass SYSCLS EDITABLEDOCUMENT in the Class Browser
   
4. Put the SYSCLS_EDITABLEDOCUMENT via dragging and dropping in the Relation Editor and navigate to the Classification
   
5. Now all Instances of the created MetaClass can be set either editable or not by checking "EDIT_FILE_ALLOWED".