XSL and Schemas

[Crisps]

Hi,

I have an XSLT document that parses and incoming XML document. Is there anyway to validate that the incoming document matches a schema as a part of the transformation. I would like for example to say in the XSL itself something along the lines of.

IF document matches SCHEMA THEN
PARSE NORMALLY
ELSE
CREATE VALIDATION ERROR NODE
END IF

I have no access to the code where the transformation is called, just to the stylesheet itself. There is a function import-schema but I am not sure what this does.

Has anyone got an example of how I could do this?

Thanks,