I’ve tried to do the same thing, unfortunately it seems like BFO does not support this:
http://bfo.com/faq.jsp
How do I set headers and footers for specific pages?
The Report Generator userguide has a section devoted to headers and footers. In version 1.1.x of the Report Generator the options for setting headers are:Setting them for specific pages using the page selector in the style sheet.
Setting them in the tag and tags, in which case the header and footer will be changed from that point forward.
Setting them for odd and even pages using the CSS2 right and left selectors for the body tag in the style sheet (see the “examples/dynamic/bigtable.jsp” example in the download package).
At the moment we do not have a facility for explicitly assigning a footer or header to the last page in a document when the number of pages is unknown.