FreeBSD-update fails downloading upgrade information

I'm running a 6.3-RELEASE-p2 machine which I want to upgrade to 6.3-RELEASE-p6. I thought it was a good idea to start using freebsd-update for this. And already I'm running into trouble:

freebsd-update fetch
works fine, but running:

freebsd-update -r 6.3-RELEASE-p6 upgrade
ultimately results in:

Does this look reasonable (y/n)? y

Fetching metadata signature for 6.3-RELEASE-p6 from failed.
No mirrors remaining, giving up.

I've been reading several mailinglist posts about DNS resolvers not being able to resolve SRV-records, I'm running PowerDNS recursor which supports these records. This does not seem to be the problem.

After running with --debug I got the following message:

fetch: Not Found

Does this mean freebsd-update is not ready for p6 yet or is something else the matter?

(btw, I'm using the latest from a recent cvsupped /usr/src)
yes you just have to do freebsd-update fetch install

since the command your using is to upgrade to a next major version which 6.3-RELEASE-p6 is not