USPS Shipping Question

I'm setting up my store and everything is going well. I set up with USPS to use the shipping calc. API. This is the only option I'd like to offer.

Here's the hitch. I'm using a drop shipper for all items in the store. I'm located in NY and the shipper is in CA. How do I set up my shipping calc. to use the CA zip for calculating yet leave my store address with my zip?

Thanks for the help!

Little bump here...can anyone help or is this hopeless?

UPS and USPS use the configuration settings in the:
Shipping/Packaging for the Shipping from address of the Country and Zip Code ...

NOTE: be sure that you have installed the USPS May 14th Update for their server changes and price changes ...
http://www.zen-cart.com/forum/showthread.php?t=65732

And where do I find those config settings?

Found it! Thanks! I'm just need to update the files for the May 14 change and I'll be all set!

Nother question related...I did some tests and it seems my shipping is coming out correct when compared to the USPS site. Is there any reason if everything is working why I should do the May 14 update or should I leave everything alone?