Barcode readers and mobile e-invoices

During summer I was toying around idea how mobile payments could be combined with barcode readers. Some of my friends have with their iPhone online banking app. They can scan new paper payments with camera and barcode. When scanning picture they upload document info to banking app and pay. It seems to work fine with them.

For this idea, I started to make idea, where one phone app could generate barcodes, send message to email-address or as sms to phone. Receiving party would get message, open his app and read barcode. This message would be then read by own banking app on phone and payment would be executed by phone. 

Only it requires one app which generates barcodes including my own bank info and other payment info. This app could be on phone or stand alone service online. Other app, even inside mobile banking, then would read this message and execute payment. If I would not like to pay with my phone, I could read same codes from my PC using my online bank.

This kind of idea would help SME's to send e-invoices straight to bank customers. Even micropayment could be managed same way. 

How do you see this idea? 

With pictures it would go like this.

Adding in App new payment to be send

When paying in mobile banking app, there would be barcode reader with camera or dowloading SMS message/e-mail.

Let me know if this could be killer app for e-invoices. At least with this system most of us would like to send/lend money for friends with ease. Foe small or medium size companies, it would make billing easier and cheaper. If compering price of send SMS or email to paper, it would make sense.