Raise a credit memo for serial tracked item when using bins

Scenario:
My customer has a location called '00' which uses bin mandatory, a serial tracked item was sold from this location from bin 'PK' with the serial number 'S000000006'. The inventory pick has already been posted and therefore we need to credit the sale and sell the correct serial.

Method:
I have raised a credit memo and used the 'Get Posted Document Lines to Reverse' function to pick up the line from the Posted Shipment. Two lines are created, the first a desctiption referencing the Shipment number, the second is the item line with the location '00' correctly specfied, but with no Bin. (When viewing the available lines to reverse I can see that the bin is correctly entered on the line, it just doesn't come through to the credit memo )

Problem:
This credit memo will not post as bin mandatory is turned on, I can't enter a bin manually as an error states that item tracking must first be removed. If I remove the tracking information and enter a bin, I am then unable to re-enter the tracking information for the serial number as it is not available for selection from the list. ](*,)

Has anyone got any suggestions as to how to work around this issue, code changes are welcome

Many Thanks
Andy