Is this the duck sauce you're looking for?

Definition: Duck sauce is another name for Plum Sauce. The name "duck sauce" comes from the fact that Western Chinese restaurants began serving it with the pancakes that go with Peking Duck, under the mistaken impression that this was an authentic practice. (In China, Peking Duck is traditionally served with hoisin sauce). But whatever name it goes by, plum sauce makes an excellent dipping sauce for appetizers, such as Egg Rolls and Spring Rolls.


http://en.wikipedia.org/wiki/Plum_sauce

If so, I'm sure it's available on the West coast, maybe even in China.