convert a template in to another template using big commerce

A template has to be converted in to webpages that are based on the templates of bigcommerce ([login to view URL]) or ekmpowershop ([login to view URL]) online shopping cart portals. we are planning to host an online shopping portal in any one of the above portals. but we are not satisfied with the existing templates of ekm and bigcommerce. so we would like to convert one of the generic template that we liked in to either ekm or big commerce template mode.