I'm trying to create a simple import form in my project by using the FileUploader whereby users can upload a XML file which then gets mapped to objects. However I'm forced to create two objects in my metamodel which inherit from XMLDocument and FileDocument due to security reasons (MxAdmin has no right to create those objects in the System model). Is there a specific reason for this? Now I'm forced to pretty much duplicate the relationship between the two objects in my own meta model.
It is true that you must inherit from FileDocument and XMLDocument, however the association System.XMLDocument_FileDocument is inherited by your object that inherits from XMLDocument. So you do not need to create this association yourself.