With the change to the new server infrastructure, we also changed the way developers can use dput to upload their source packages to the autobuilder. We created a special host named drop.maemo.org for uploads using dput (and scp). The uploading to Extras wiki page has been updated with the correct information. Short story: replace garage.maemo.org with drop.maemo.org and continue like before.
Another change we had to make was how packages are promoted from diablo Extras-devel to Extras. The old promoter was no longer suitable for the current setup and needed to go. Promotion now works the same way as it works for fremantle Extras-devel to Extras-testing (direct promotion). The package interface for diablo Extras-devel can be found here.
There are still a few features missing for the diablo part of the packages interface, but promotion should work. I'll add build logs and context sensitive searches at a later point.