Just trying to do the exact same thing myself. Will keep digging for an answer and/or hope you get a helpful response.
Hi Jaekro,
I’ve just spent the last 48 hours with similar issue. Colleague discovered solution to our shopcart problems – somehow the last release of WP E-Commerce changed the way target market/location settings are handled within categories and sub-categories. Basically if a parent category, and its sub-category have a target market indicated, as well as the overall shop settings (even if it’s the same market/country), it causes some issues with the shipping part of the shopcart.
Try turning off all target markets – except in the overall shopcart settings, and see if that helps?
MA
I’m finding a similar issue – shopcart’s shipping has some bug, causing checkout to be broken, without any changes or updates having been made to the plugins or shopcart itself.