Probably the best way is to go to Taiwan and hand carry it back yourself. If that's not an option for you I'd order the DX2 separately from the DiskDual. First order the DX2 (make sure you pay the extra $20 to get a 64M unit). Get the fastest shipping you can afford. If you get a next day air shipment customs isn't going to have much time to look at it. Next best is probably EMS shipping. Then, once the DX2 arrives, order the DiskDual.
Even if customs takes the unit, it's been shown that if you make a good argument you can get it returned.