Not the solution, but a "pragamtic workaround" to proceed work.
I'm far away from be an expert on this, but my inspration told me to remove this "signature things", so I removed the line:
<xs:element ref="ds:Signature" minOccurs="0" />
And see... the DataSet will be created and I can Display the tables.
So at least you can go on with coding and parallel you can search for a clean solution of the above.
I don't know what I'm doing, but I'm doing it good :)
Regards