How do I tell SAXON to not validate the value of xsi:

Hi Folks,

I am running saxon9he from a command line.

I have a simple XSLT program that goes into a large XML document and copies
one element and outputs it.

When I run the XSLT, I get this error message:

Error in xsl:copy-of/@select on line 13 column 61 of test.xsl:
  XTTE1510: Unknown xsi:type in element being validated: Vor
  in built-in template rule for /Test in the unnamed mode
Unknown xsi:type in element being validated: Vor

I think that error message is saying that SAXON found this element:

<foo xsi:type="Vor">

and cannot validate the Vor type. Is that what the error message is saying?

I am not doing schema-aware XSLT, so I don't understand why SAXON would be
trying to validate Vor.

How do I tell SAXON: don't try to validate the value of xsi:type?

/Roger