This one was raised up at http://lists.debian.org/debian-mentors/2007/03/msg00336.html.
It is currently not possible o divide between copyright and legalnotice for upstream software (or "the product") and the manpage. The copyright.section element processes all copyright elements and then all legalnotice elements. There is no way to write down separate copyright and legal notices for the product and the manpage.
One idea to solve this could be to use the role attribute and process first role="product" and then "role="manpage". Another idea could be to use a processing instruction. What is your opinion?