If automated online repositories configuration fails

It happened twice to me, so I guess it can happen to everybody.
After installing 11.0 from DVD, I wasn’t offered a full online repositories configuration. Rather, the system configured itself with the 3 basic repos (OSS, NON-OSS, Updates).
That means that if you want to add the extra repositories, you have to do it manually. It can be a lot of work, as the list of extra repos is very long:

Package Repositories - openSUSE

Additional YaST Package Repositories - openSUSE

So what to do?
This is what worked for me:
I deleted the already configured repos (the 3 basic ones)
And presto, The Updater applet offered me to configure the repos, and everything (well, almost) was available for me to choose from.

Edit: I believe you must remove every source for this to work, including the DVD. You can easily add it again later.