HowTo merge two IPS repositories

I wanted to merge a repository with KDE 4.4.4 packages with another one with KDE 4.4.5. First I went through the pkgsend/pkgrecv man pages but only succeeded in the pkgrecv part (pkgsend just stalled without any hint on what's going on). Then I asked at the #opensolaris IRC channel and it turned out to be really simple:

$ export TMPDIR=/var/tmp
$ pkgrecv \
-s file:///export/home/pkgserv/repo445/export/home/test/repo \
-d file:///export/home/pkgserv/repo 'pkg:/*'

Setting TMPDIR properly is quite important, because pkgrecv by default caches the files in /tmp, which is practically your RAM and the repo has ~1.6 GB ...
/export/home/pkgserv/repo445/export/home/test/repo is a directory containing repository with KDE 4.4.5
/export/home/pkgserv/repo contained KDE 4.4.4 and now contains both