So, I THINK I may have just seen what you're seeing. It appears - from my minor testing - that there is a disconnect when the user is created/added inline on that portal administration page.
Try this:
In AAA, create a local repository user (if one exists that you want to use, delete it/save/recreate).
Go BACK to the portal administration and select to add a login configuration.
Choose the existing user you just created and assign it the admin role.
Try logging in again.
I could not do this when creating the user inline in the portal administration "add login configuration" dialog.
If you see the same results, I'll confirm again and then open a bug. Regardless, let me know either way.
