Field "settlement cost element" (COAS-KSTAR)

Hello,

We have activated the field "settlement cost element" (COAS-KSTAR) for internal orders in customizing. Now this field is only visable when creating a new internal order but we also want to use this field for the existing internal orders.

How can we make this field visable for exsting orders or is this just not possible due to earlier settelement on the order?