The problem is that logic boxes only expects to receive the following variables from the postpayment.jsp:
transid
status
rkey
checksum
sellingcurrencyamount
accountingcurrencyamount.
So there are no fields to return a reference number to. I considered trying to append the reference number to the description field or even to store it in the session, but there is no description field being passed back from the postpayment.jsp and even if I put ref in the session I have no way of knowing if LogicBoxes would pick it up.
I spent some time on the LogicBoxes web site looking for answers. I didn't find anything that would help. I would suggest that you open a support ticket with them explaining the problem and asking them to provide some guidance.
Has anyone else integrated LogicBoxes with KNet? If they have, then that may have faced a similar situation and may have found a work around.
I was hoping the LogicBox WebSite might have a "forums" section that I could search for clues or post the question myself. The only thing I found was their support system.
So if LogicBoxes can provide some guidance then I will be more than happy to integrate their suggestion into your current system.