pkg.freebsd.org behind proxy doesn't work

[Lars Engels]

Hi all,

how can I use the official pkg.freebsd.org mirror behind a corporate 
proxy server?

With 10.0-RC1, pkg-1.2.3 and the stock /etc/pkg/FreeBSD.conf I get:

# pkg update
Updating repository catalogue
pkg: http://pkg.FreeBSD.org/freebsd:10:x86:64/latest/digests.txz: 
Service Unavailable
pkg: Unable to find catalogs


So apparently the proxy doesn't do SRV lookups. I don't administer the 
proxy, so changing
that is not an option.
What can I do to use our official repository?

Lars