Installment Payment Plugin

I am looking for a payment mechanism that will allow installment payments. My client has requested that registered members can purchase items and using what ever payment plugin, allow the member to pay a fixed deposit (example 20%) and then set up a credit agreement whereby a fixed monthly amount is taken from the member over a 12 month period.

I am aware of subscription payments in Paypal, but i am not sure if this will work as described or if there is an available plugin.