We have a client who deals with insurance claims and needs the ability to record an SOP invoice for say £1000 + VAT minus a nett deduction of £200.

So they enter a line as showing Claim £1000 at VAT code 1.

Then enter a 2nd line as  Less Excess 1 @ -£200 VAT code 0.

The order will not allow saving of the order with an overall negative nett total for any given Tax code.

Also will not allow even the VAT amount to be overriden to resolve the issue.

Having to post currently as a Sales Ledger only Invoice transaction where you can either override the VAT or record overall negative values if desired, problem is you cannot print off an invoice from this area of the system.