There's one solution for this problem, that works all the time:
NEVER, EVER ORDER ANYTHING FROM NON-EU BASED DEALERS/MEMBERS.
My record with the Asian dealers: 3 orders -> 3 customs problems.
My record with the EU/US based dealers/members: 36+ orders -> 0 customs problems.
Wonder if there's a formula somewhere...
Just for the record: The last watch from an Asian dealer got sent via registered airmail, and it got stuck into customs too. So it's not a bullet proof way, either. I did nothing, I just wait until they'll send it back.