Solution : https://service.sap.com/sap/support/notes/890228 (SAP Service marketplace login required)
Key words :
OKB3: Creating cost element category 90SAPMKC01, RKBIKA00, SAPMSBDC_CC
Related Notes :
| 395762 | Special balance sheet account: no cost center acct assgnmt |
| 75980 | Creat.cst elem: KS036 "G/L acc. & is a bal.sh.accnt" |