MarketPress can't use PayPal Website Payments Standard?

Have just installed MarketPress and gone through the pain of upgrading WP e-commerce in order to migrate products across to MarketPress but when I got to setting up payments I find it doesn't support PayPal Website Payments Standard! I know it accepts Express Checkout but what are the implications of switching an account to Express Checkout? I see you can only use one method at a time in PayPal so if using the PayPal account for other sites and payments what would happen to those if I switch over to Express Checkout?

Seems very unusual to offer Express Checkout and not Website Payments Standard like everyone else!

Would appreciate a speedy response as in mid-migration and this is a bit of a show stopper :slight_frown:

Thanks.