How to add a trade-in line item (i.e. give cash back to discount a deal) to BCM 2007

How to add a trade-in line item (i.e. give cash back to discount a deal) to BCM 2007http://192.168.2.20/blogs/doverton/archive/2007/07/12/how-to-add-a-trade-in-line-item-i-e-give-cash-back-to-discount-a-deal-to-bcm-2007.aspxSomeone asked me how to do this and I discovered that you can't have a negative discount percentage, negative quantity or negative price. So this makes it impossible to do... well, no, but it is not quite as easy as we would like. To make it workenCommunityServer 2008.5 SP2 (Build: 40407.4157)