I slightly modified the title of your post to reflect the fact that what fails is loading the elements for auto fill in the auto fill property page. The actual auto fill implementation should work regardless of how the connection is established (either via Secure Gateway or direct).
So the current workaround is to manually configure your auto fill mappings. You can find more info on how to do this here: https://www.royalapps.com/go/kb-all-web-autofill
I have the same issue, auto fill does not work when you access a site via Royal Server/secure gateway/proxy.
The KB article is of no help.
There's no way to enter these elements manually:
Would you be able to let us know what is not working and if you were able to try the Key Sequence Task workaround mentioned in the Knowledge-Base article?
It seems that according to your screenshot you are providing the $EffectiveUsername$ value for the "password" element
We can also try to help you directly. For this please open a new support ticket with the problem description here: