Hi,
For those who may not be aware Safaricom now has an online payment gateway which you can integrate into your applications/websites and have transactions processed seamless.
My tests of the gateway show that its integrated with M-PESA as well as Paypal which means you can have your customers choose to pay you via M-PESA or via any Credit Card/Debit Card.
Contact me off-list for more details or for me to put you in touch with the integration team (not sure i can publish their contacts here without their info).
Regards