Sorry to be a pain if this has been asked before, but how can I change google base feeder to submit my prices including VAT ?

Google excluded our feed in January because our prices weren't including VAT. The only way I've been able to submit a feed since in through downloading a tab delimited version of the feed and editing it myself. Timeconsuming and brainhurting

So now I'm hoping to get it automated again. Any help?

Thanks