Incrementing a page number with xsl-fo

I need to create a page number in a footer when the work package ends with a
odd number that looks something like this:

0001-5/6 blank

How can I generate the "6" onto page 5? Page 6 is blank and doesn't actually
exist so I can't seem to reference it with <fo:page-number-citation>.

Is there somewhate I can take the current page number and just add 1 to it?


Charles Flanders