Condition type in shipment cost document
I am facing following problem while creating shipment cost document.
I have created condition type ZFLT (class : Prices) and is the only condition in shipment cost pricing procedure. While creating shipment cost document i am entering ZFLT manually more than 1 time and system is keeping all the condition active.
I have observed that in sales order if we enter such condition (mean whose condition class is "B-Prices") than system automatically makes earlier record inactive. But in case of shipment cost condition this is not happening.
How to control this ?...I required that shipment cost document could not be created with more than one active record of the same condition (i.e. ZFLT in my case)....Pl sugest.