• Download the database.
• Enter in your Zip Codes.
• ReUpload your File
• Add the line
  <input type="hidden" name="MULTI_ZIP_EST_TAX" value="yes"> into your "subtotal" page.

Note: Custom Cart users can also just enter the zip codes at the control panel interface.

Additem can specify an override tag to force a particular item to be shipped out of a given store. The tag is called "ItemSourceZip". Submit it along with the zip code of the store with the block of ItemID, ItemDesc, etc.