How to cancel an invoice without deleting it?

[bouillin]

I created and sent an invoice to a customer, then I realized the invoice was not appropriate, and simply would like to cancel it. I don't want to delete it, since I'd like to keep track of my mistake. I'd like simply to make it void. Removing all items does not help as EI refused to zero the invoiced amount...

 

My workaround was to create a fake item of 0,01€ (!) add it to the invoice and create afake payment of 0,01€. Not very neat.

 

Adding a "state flag" to the invoice would solve it I believe. Something like: PAID/VOID/etc

 

Any idea?