Validating XML against schemas

Question

Hi there,
I have the following question. I have a main schema that is derived from multiple schemas. I want to validate my xml against these xsd's. How can we do that?
In Multiple schemas that i have all the elements and attributes have been defined and they are being referred using the ref attribute.
I want to do the following: ( Read XML and load it into a dataset, which is not working due to multiple schemas)
objXmlDataDocument.DataSet.ReadXmlSchema("C:\test.xsd")
objXmlDataDocument.Load("C:\test.xml")
dsXmlData = objXmlDataDocument.DataSet
Any help would be appreciated.
Thanks,
vsr