Viruemart and XML component modification

Hello, I need some virtuemart plus custom xml component exporting to Google Base modification. Currently the xml only exports in default language and default currency. I need the xml file to get exported in a specifically set language, currency and tax mode and dynamically create a link to product detailed product page with the same language, currency and tax mode. I need additional feature in the xml component: to append to the product description 1) meta deacription based on if the product has or doesn´t have short_description 2) all product_type values (yes/no) Vistor will have an option to choose if he/she wants prices to be displayed with or without taxes (front-end show price with tax enable/disable) and all the prices will be respectively signed (incl. tax/excl. tax). I use joomfish and joomsef, so all the work must be compatible with these components. Furter more I need to fix a small price-> paypal currency bug and enable EU vat check for merchants with online vat number verification. The output should be delivered in a zip file with all the updated files in appropriate folder structure and clearly signed all the modifications (install) along with all the files in an original version