Sorry, but I don't think there is any direct way of doing this. One reason is that if you append XML to an existing XML document, the result is not well-formed XML. Another reason is that if you append to the same file twice within the same transformation, the order of the results would be undefind.
What you could do is to specify a user-written SAX ContentHandler as the output method, and organize the appending from within your own code.
Michael Kay

From: [] On Behalf Of Steven Anderson
Sent: 03 May 2005 00:54
Subject: [saxon] saxon:output and file clobbering

I’d like to be able to use saxon:output (or xsl:document) in Saxon 6.5.3 to concatenate information on to the end of existing files.  Is there anyway to do this?  When I use <saxon:output href=”foo.xml” method=”xml>, foo.xml gets clobbered.  I’ve looked at the doc, and I didn’t see any attributes that could control that.