Handling charitable donation as a discount on an invoice

[Kevin Wilson]

Hi all,

I'm currently converting from an ancient version of QB to GNUcash, and 
re-entering invoices from earlier this year. I'm having a problem 
working out how to handle one particular invoice where I billed for some 
hours of work to a local charity, then added a line with a $100 discount 
as a donation to them. In QB, I had an invoice item linked to my 
charitable donations expense account, but as far as I can see in 
GNUcash, items on an invoice can only be connected to an income account. 
If I handle the donation as a discount on the invoice, I can only choose 
an income account to  connect it to.

Is there a way to post a charitable donation directly to an expense 
account from an invoice, or am I barking up a dead tree?

Kevin