Okie~ the problem now is how to set the cost element to be created automatically when we create a GL account.
I'm pretty sure we can set this in the customizing but i'm totally forgot, sooo..after a while checking here and there and of course asking people, this is how you set it :
1. Step 1 : Customize the Chart of Accounts
SPRO --> FI New --> General Ledger Accounting New --> Master Data --> GL Account --> Preparations --> Edit Chart of Account Lists .
Here, double click at your Chart of Account (COA). In the tab "Integration" , set the Controlling Integration to "Automatic Creation of Cost Elements". However, if you set this, then every time we create a Profit/Loss GL Account, the system will automatically create the Cost Elements. If the user desire t0 not controlling internally every P/L GL Account, then avoid this customizing. Instead choose "Manual Creation of Cost Elements"
2. Step 2 : Check the Automatic Generations of Cost Elements
SPRO --> Controlling --> Cost Element Accounting --> Master Data --> Cost Elements --> Automatic Creation of Primary & Secondary Cost Element --> Make Default Setting
Set all the number range of cost element for the COA maintained at step 1. Here you should maintain which cost element number range goes to which Cost Element Category.
For Example : Account 40000000 to 499999999 goes to Cost Element Category 11 (Revenues).