> Again, my comments above about issues with using bitcoin: URI for everything. Also, why do you want to bloat the blockchain with unnecessary refund transaction data?

I don't, sorry -  I was just kind of thinking out loud and explaining what happens when you stuff that into a URL.  

My conclusion at the bottom of that post was to keep BIP 75 the same, don't change a bit, and stick any subscription information (future payment schedule) in the PaymentACK.   Then the wallet then re-initiates an invoice (unattended or attended.. up to the user), after the subscription interval is passed.  Subscriptions are pretty important for Bitcoin to be used as a real payment system.