Hello Elke,
I am noticing weird behavior with download portal. Please follow these instructions:
1. Go to your Download Center and search for CA Advanced Authentication.
2. Click on top of CA Advanced Authentication For Business Users MULTI-PLATFORM for example.
This will take to you to the next page were you will find a scroll down menu to select Release and Service Pack
3. Select required Release and Service Pack and it will return the results for your request.
4. Select 10.5 or HF1 under FILTER SEARCH RESULTS.
5. Now from top right Release drop down menu select any other version. It won't display anything now. I need to start over again to download from Download Center.