Importing entity from metadata aggregate file via xml api fails with a 400

I am able to import individual metadata entities via the xml api without issue.

When trying to import metadata entities extracted from an aggregate file I receive a 400 and no other information.  Attempting to upload the same xml via the UI results in a 400 .. undefined.

An example xml file that fails is attached.

This is most likely namespace related. In the aggregate file everything is wrapped in a <EntitiesDescriptor> tag that defines all the namespaces.  I had to add the namespaces to each individual <EntityDescriptor> to get the Perl XML parser to accept it.