If I made a cheque in octobre 2012 and the payment realized in the bank in 2013 , i.e this month... and nothing has been posted in the supplier account i.e neither an invoice nor the payment... so can I post the invoice and the payment in this month, in this new system or? Because the payment will be shown in the bank statement of this month ( jan 2013).

You will post the payment when you write and mail the check, not when the check clears. So in your case the payment was made in October, because you wrote and made your payment in October.

Between when you wrote the check and the check clears the bank, the check will be outstanding.

You should be doing a Bank Reconcilliation every month after you receive your bank statement to bring your actual bank balance and your personal or company account balance into agreement.

So to account for your check that has not cleared you would subtract the check amount from the actual bank balance. For an example your have $1,000 on your bank statement, but your bank account says you have $900 and you wrote a check for $100 during the month and has not yet cleared. So you sbtract the $100 from your $1,000 and you end up with an actual bank balance of $900, which equals your account balance.