Invoice schema does not import correctly
I'm working on PEPPOL/UBL for a customer, and have downloaded the 2.1 UBL schemas. The UBL-Invoice-2.1.xsd does not import correctly - there's a missing dependency for the http://www.w3.org/2000/09/xmldsig#:Signature element. That's in the UBL-xmldsig-core-schema-2.1.xsd file, which is not imported
I tried adding the UBL-SignatureAggregateComponents-2.1.xsd file as an import, as that in turn imports the xmldsig namespace, but that's still not working. A check of a couple of the other maindoc schemas suggests that this is a general problem.
Has anyone else hit this, or found a way round it?