I'd like to sell a subscription service initially using the (easy to use) Web Payments Standard buttons, but later implement against the WPP API. My question is, what will the migration from WPS to WPP look like, both for the merchant and the buyer? Will I be able to upgrade/use my existing PayPal account that accepts the subscription payments originally created through the WPS method once I've migrated to the WPP method? And most importantly, will the buyer be able to modify their subscription originally created with the WPS method through my own WPP backed interface? Will the two merchant account have to be totally separate? Will I be able to reference the WPS created subscription through the WPP API? Will the management features be the same between the two methods?