changing the package path variable

[Nikolas Britton]

Here is where portupgrade is fetching
ftp://ftp2.us.freebsd.org/pub/FreeBSD/ports/i386/packages-5.4-release/
                                                                     
^^^^^^^^^^^^^^^^^^^^^^^^^

Here is where I want portupgrade to fetch from
ftp://ftp2.us.freebsd.org/pub/FreeBSD/ports/i386/packages-5-stable/
                                                                     
^^^^^^^^^^^^^^^^^^^^^

What variable do I set to change this? it's driving me f'ing nuts.