I never used this before, to tell you the truth. But this seems to be quite straightforward: SM30, view V_T8A_BILANZ, add your controlling area, enter the value 1 (profit center balance sheets).
Then you have to populate the PC field in all B/S account line items as well (perhaps you do already). Of course, F.10 will post to b/s accounts as well.
Then, I think you should check structure SAPF100_OUTIN in SE11, if the PRCTR field is already included. If it is (should be), probably you only need to carry out F.19 and check the postings
Hope that helps, points welcome