R&S is really messing up their support, it seems.
I registered on their support site for downloads and I have been able to download firmware updates recently.
Just now I tried to check for a firmware update again and logged in. I now needed to click a button to gain access to "premium content". When I did, I received a confirmation mail that my request was being processed. 6 minutes later I received an e-mail telling me my request was rejected!
So, I bought 3 R&S products over the past years and now their system rejects requests for firmware updates. Apparently my business isn't premium enough.