I have one module where I have my XSD schemas, where one schema can reference an other using relative path within schema location:
Spring web service has a way to do it elegantly actually.
All you need to do is to define a SimpleXsdSchema bean with the right id (which will be used as the xsd name without .xsd) in the bean definition xml file, something like below
More information (including an example) can be found at the following link: Static WSDL with imported XML Schema in Spring Web Service