unfortunately, there's no known way to do this, yet. SOAP::WSDL uses XML::XPath for parsing the WSDL, and XML::XPath unfortunately cannot resolve the import-Element.

I would suggest to download the WSDL, store it on disk, and insert the schema found at the specified URL into it. Unless the WSDL changes on every call (which is a bit unlikely), there's no reason why you should not be able to change it - storing it on disk instead of using a http(s) URL is even recommended for performance reasons.

Regards,

Martin