RNC and inclusion in XSLT-generated XML documents as text?

I'd like to include RNC examples in XMLSPEC just as we include XSD examples,
but I can't see how to do it.
I do see this ancient message from Eric van der Vist about including
plaintext with an XSLT extension function, but surely there is now a
portable solution I've just overlooked?
Is there a standard way to include RNC (as opposed to RNG) in XML documents
as text?

http://www.biglist.com/lists/xsl-list/archives/200011/msg00768.html