Banking integration

I've started translating FA into Norwegian - and think it will be a very welcome alternative to the expensive proprietary applications used here.

However there is one type of functionality that most companies would want - electronic banking. The system is used by all banks in the country and works as follows:

Accounts receivable:
Customer invoices are printed with a special numeric field, containg customer number and invoice number and a simple control number. For example NNNNIIIIXX where NNNN is customer #, iiii is incoice # and xx is calculated from the other two.

When customers pay they enter this number as reference. The result is that companies download a file each morning containg date, amount, reference for all yesterdays payments.

The ERP system then read that file and all appropriate transactions are automatically updated.

All commercial ERP systems has this.

Accounts payable:
Same thing but in reverse. You register the reference with the supplier invoice. The ERP creates a file that you SEND to your bank. After that you download a file containing all actual supplier payments done yesterday, and the ERP take care of it.

By the way, almost nobody use checks anymore.....

My question the is:
Now, how difficult (or expensive) would it be to develop an addon that would do this?

It seems that AF is designed for pretty large companies. Not having this functionality would keep a lot of larger companies in Noway from beeing able to use it.

Thanks for reading!