As you probably know Microsoft forgot to include Xsd import to the
Biztalk Editor. In order to load your existing Xsd's to the WebDav
you will need convert them to the Xdr/DTD and only then import them, using
the Biztalk Editor.
We spent a lot of time trying to make this process as painless as possible
and here it is: the XSD to Biztalk Document definition converter:
Please submit the XSD specification, compliant with the
http://www.w3.org/2001/XMLSchema standard.
Sorry old xsd format is not supported.