accounts not hitting sepearte G/L account
we are working with account assigned Purchase order ( P) projects where the system is picking the G/L account thru valution class from the OBYC and we are giving the WBS element.In my PO we have different conditions for base price , frieght and others.
my goods reciept is nonvaluated and when i doing the invoice my conditons are appearing as seperate line items but the account is same as what is in PO.
My requirement is that i wanna to post Material cost and fright to sepearte G/L acount .
To me it seems that it should to that G/L account.
I wanna to post material cost and freight cost to sepearte ..........
Please suggest me how i should move so that my requirement can be meet.
Thanks and regards