I need a purchase order Payment Module

[proexec]

I want to add a custom payment module to zencart.
I want to add a module for purchase orders.
I just need to have the name purchase order and then a field for the customer to fill in their purchase order number.

This module will work similar to the checks/money order module but with the filed for them to fill in the purchase order number next to it.

I hope I explained this well enough.

Can some help me out with this?
Thanks

[Merlinpa1969]

check the downloads section should already be one there

[proexec]

Thanks very much.