Automated home encryption and noexec mount option

I'm using Ubuntu 13.10 and the integrate home encription via pam and eCryptfs.

For security reason I've mounted /home with the noexec mount option, but that don't affect users with encrypted home (since it's mounted separately at the user's login): how can I set the automatic mount and add the "noexec" option?

I've googled a lot and searched the system for a config file or a script to edit, but to no result, so asking here is my last resource.

Thanks very much in advance

Wilson