SSH with RSA Keys on AC66U

First of all, thanks to Merlin for this great Firmare!

I just started using it on my AC66U and have a probably trivial question... just couldn't find the answer here, maybe someone could help.

Automatic login with RSA Keys for SSH works fine, but since the .ssh/authorized_keys file gets lost on a reboot, I am a bit puzzled on how to get it function permanently.

Is there any way to get the .ssh/authorized_keys file on a permanent part of the filesystem and have it considered by the sshd?

Thanks a lot