automatic characteristic value assignment

Hi,

    I am trying to assign the revision level on the production order or purchase order to the batch characteristic of the batch which is being produced/purchased. I want to do it automatically. Does any one know of any way to get the value from the EKPO-REVLV or the AFKO-REVLV tables and populate that in the batch master ? I tried the reference characteristc option in CT04 but that does not work.

Thanks