capture change log for field AUDISP(Reservation Relevance/Generation of Purchase Requisition) in CN60 transaction

Hi Experts,

When we change the value of field AUDISP(Reservation Relevance/Generation of Purchase Requisition) in network activity Extnl tab in CJ20N transaction that changes should capture in transaction CN60(Change document). For this we checked the change document check box in data elemnt AUDISP. But changes are not getting in transaction CN60. Please suggest me how to acheive this and which table contains AUDISP filed values. I tried to find the table but could not able to find.

Appriciate your suggestions

Regards

vijay