Ecommerce Module & Utility Bills

Hello!

I have recently downloaded the ecommerce module and installed it on a development site for the Town of Blackstone. The town is interested in allowing its citizens to pay both utility bills and taxes online. I have suggested using PayPal to handle the transactions, and am hoping to also make use of the ecommerce module.

I began setting the "products" up as donations, planning to use the locale module to change the wording to make it appropriate for billing rather than donating. It seemed that all was going as planned, except for one thing. I need to be able to allow the person who is attempting to pay their bill ("donation") to enter their account number in a field on the product page. Once that account number is entered and the utility bill is paid, the account number needs to be (1) provided in the confirmation email to the payee and (2) somehow made accessible to the town treasurer, presumably in the backend at admin/store/transaction someplace.

Does anybody have any idea how something like this could be accomplished?

Thanks for your help!