My Trade In work-around
Since LS does not offer a trade-in option I was left with finding a work around.
I searched the threads, and did not find anything that allowed me to apply the trade in value to a sale, and properly asses the sales tax to the difference, not the whole.
Here is what I have come up with. I created a Discount called Trade-In, and assess a value to it according to the item being traded. Then when I create a sale, add a customer, and apply the discount it deducts the trade value and does not tax the discount amount, it only the taxes the difference.
When I do the next trade it all I have to do is adjust the value of the discount.