*doh* :P What you can do until (if ever) we add some way to "block" auto-associating a contact and friend is to change the URL of the contact. There's typically a part of the URL that looks like ?id=0000123456789 - if you change that number, it won't match any of your friends and therefor not get updated. (Just make sure it's not the ID of a "real" friend - change it to ?id=BLOCKED0000123456789 and you'll be safe.)

It'd be great if you could take the time to file a bug report and ask for a feature where we "block" auto-association for a certain contact. If you'd like to, go here: https://bugs.maemo.org/enter_bug.cgi?product=Hermes