noNamespaceSchemaLocation

I do an xsd:import

xsd:import namespace="" schemaLocation="bla.xsd"

and bla.xsd doesn't define a namespace for its elements.

No way. I get an error

Imported schema has a target namespace "null" that does not match the specified ""

If you specify a namespace, Eclipse complains that it's different from the one used in bla.xsd.
If you leave it empty, "", still it complains. If you omit the namespace="" clause, again it complains. I have tried xsd:nil, no way.

The only way is to use

xsd:include schemaLocation="bla.xsd"

or

xsd:import xsi:noNamespaceSchemaLocation="bla.xsd"