Virtuemart, v1.1.3, the eCommerce solution which can be bundled with Joomla does not include a native tax code module which works with U.S. states which have any kind of complex regional or district sales tax structure. Off the shelf, the best you can get is a single tax rate for an entire state. The fix which I developed is a more simplified, yet versatile, version of the original fix that was created for Virtuemart 1.0.x. Besides the zip code and custom tax rate need I am also including some loose documentation on how to change some display preferences so that for U.S. customers taxes do not get confusingly added to product prices.  Note that the .zip file has been updated for Virtuemart 1.4 and also includes the relevant ps_checkout. (more…)