Bills against invoices

[Wouter van Marle]

Dear all,

I've a maybe peculiar problem (though I don't call it that odd) with one
of my suppliers. We invoice and bill each other, both ways. I've a
problem arranging payments well, using GnuCash 1.8.11.

I have two issues here.
1) when I have entered a company as "Customer", I have to add them again
as "Vendor" to enter bills from them. That's not nice.
2) how to pay invoices with bills?
For example:
I send company "Foo" an invoice for $100 for provided services.
But besides providing services, I also purchase materials from them. So
they send me an invoice for a shipment of say $250. Now I want to make a
single payment to them of $150, to keep things easy for me. I haven't
found an easy way to handle this.

Other example:
I sell material to company "Y", and send them an invoice for that. They
receive the material (in my business that is after payment of the
invoice), and material is not good, so they claim me back. Now they
basically send me a bill of say $21 for that claim, but as I have sent
them an invoice already for next shipment of $300, they make payment for
the next shipment to me of $279 ($300-$21 = $279). This is also tough
for me to book.

Currently I book those situations though a cash account (no actual
transactions), but it's not elegant or transparent.

Any suggestions on this situation?

Regards,
Wouter van Marle