[ic] credit items

[David Etheredge]

I have tried and can not find a way to get interchange to accept a negative
value for an item.

An example:

Item            Descr.                                            amount
hamburger    hamburger, delux                              2.25
no-cheese    customer does not want cheese        -0.35

                                                        Subtotal        1.90

These are not actual items for us, but I do need to be able to credit back
some negative value options.

Thanks,
Dave