I have yet to convince the pub.xslt.Transformations:transformSerialXML service to generate indented XML, despite including an indent=“yes” directive in the header. Is this a fault in the service, or a fault in my use of it?

My template starts with the following:

<xsl:stylesheet version=“1.0” xmlns:xsl=“XSLT Namespace”>
<xsl:output method=“xml” version=“1.0” indent=“yes”/>

I guess it depends on the processor.
But you can easily indent the generated xml by using StringToDocument and DocumentToString service.
HTH