I decided that since the site rubric pages are mostly drawn from the site.xml file in the database, it would make sense to build the menu from there too, so I replaced the code which constructs the menu from a little block of XHTML in the database with XQuery which parses the site.xml file to create a menu. This entails adding a new type of <div> to the site.xml file, which simply constitutes a link, rather than content; this is used for the contents page, which needs its own XQuery and XSLT to function. This seems to be working fine.