Validate XML against 2 XSD - validation

Question

I'm trying to parse and validate a SOAP request with SAX. Two XSD are necessary, one for SOAP envelope (http://schemas.xmlsoap.org/soap/envelope/) and the one I defined. I cannot find a way to properly validate the request against these two XSD.
Here's the code I use to parse the request and validate it against soapenv.xsd. It works fine. If I specify my XSD instead, the validation fails with "Cannot find the declaration of element 'soapenv:Envelope'".
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(true);
factory.setValidating(true);
SAXParser saxParser = factory.newSAXParser();
saxParser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaLanguage", "http://www.w3.org/2001/XMLSchema");
saxParser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", MyClass.class.getResourceAsStream("/xml/soapenv.xsd"));
InputSource is = new InputSource(MyClass.class.getResourceAsStream("/xml/request.xml"));
XMLReader reader = saxParser.getXMLReader();
reader.setContentHandler(new MyHandler());
reader.setErrorHandler(new MyErrorHandler());
reader.parse(is);
How can I specify a second XSD?
Is there a better way to parse and validate SOAP requests?
EDIT
As proposed, I created thirdpty.xsd that imports my two XSDs.
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="thirdparty:general"
xmlns="thirdparty:general"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:import schemaLocation="D:\ucfed\ValidateWSDL\src\xml\soapenv.xsd"
namespace="http://schemas.xmlsoap.org/soap/envelope/"/>
<xs:import schemaLocation="D:\ucfed\ValidateWSDL\src\xml\Presence.xsd"
namespace="thirdparty:presence"/>
</xs:schema>
I specify this new XSD for the validation:
saxParser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", MyClass.class.getResourceAsStream("/xml/thidpty.xsd"));
But still, only the SOAP envelope XSD is used for validation. If a modify one element from my other XSD, the validation does not detect it.
Here is the xml I am trying to validate
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="thirdparty:presence">
<soapenv:Header/>
<soapenv:Body>
<urn:getPresenceQuery>
<urn:origAccount uri="test#origin.com"/>
<urn:destAccount uri="test#destination.com"/>
</urn:getPresenceQuery>
</soapenv:Body>
</soapenv:Envelope>
Other ideas ?

Answer 1

Write a driver schema document which imports the other two; validate against the driver.