Include XSL-FO stored in DB

Hi,

In a service application I am generating XSL-FO's in the DB.  Translations
are also stored in the database and replaced via groovy templating.

I was wondering if it is possible to reuse some functions that one would
normally store in a seperate xsl file and include via an import.  Is there
any way to add functions to the fop 'context' so they would be available
for transformations and still be reusable for other xsl's as well (as these
generic function stylesheets would be stored in the DB as well)?

Thanks for your thoughts,
Kind regards,
Bram.