What version is your firmware? I am on 1.14 and I recall that there were some issues with Customize on that version. However, the person who write Customize created a work-around for it, don't recall where it is, and it was a bit of work, but I've been using it for a few months now.
I am assuming that you havw SMBPrefs installed and on?
Customize 2.0 is out now, so take a look at it, might fix your issues.