Problems on ssh key unlocking

I have a problem with SSH key unlocking. I have set up a profile for SSH remote backup and an SSH key used for password-less login to my NAS. I've set a passphrase to unlock this key and typed it into BIT settings dialog. I also checked both "save to keyring" and "save for cron", but what I observe is that whenever the scheduled job should start automatically, a prompt is shown to enter the passphrase to unlock the SSH key, I don't want this to happen, BIT should just work with no prompt!

Some more information. The profile is for a normal user (non-root). I'm using KDE, so the keyring service is performed by kwallet. My kwalltet does not have any password, so BIT should be able to access it with no need for me to enter the kwallet password either.
If I type the SSH key unlock passphrase, from that moment on BIT correctly does all its scheduled jobs without asking any more for the passphrase.

Am I missing something? I would just like to make BIT run automatically without any user intervention at all. Am I forced to create a new key without any passphrase?

Thanks in advance.

P.S.: a secondary problem is that if for whatever reason I type the passphrase wrong, from that moment on BIT does not ask for it any more and keeps on saying that the passphrase is wrong or that it is not available for cron. I couldn't find a way to make BIT request the passphrase again to correct the error.