u can take the existing log file in using the unparsed-text,
though cant remember if saxon supports it
http://www.w3.org/TR/xslt20/#unparsed-text
place this in a variable, which you concatanate your results to
then you could just xsl:output the whole result as text
overwriting the file.
The spec tells you that it's an error to try to read and write a single
document during the same transformation. It also says that the processor
might not be able to detect this error. In practice you can probably get
away with it, but your results will be dependent on order of execution,
and I would not advise it.
Michael Kay
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list