Google Checkout Taxes

Hi

I am setting up a new site in the UK and want to use the option within Marketpress to include taxes in the price I show. This works great until we pass over to Google checkout when it adds on VAT again as well. I have edited the settings in google checkout and tried the "do not charge tax" option and setting the flat rate to zero for both the UK and Europe but to no avail. Does google checkout support this method of displaying prices in MP?

Any help greatly appreciated!!