Post a Vendor Account Instad of the Interest account on a Flow

Hi experts:

On a 55A product type I need a specific flow to post to a VENDOR account instead of the interest account. How can I solve this issue

ie

Product 55A Transaction  200

24.05.2012 1105 Borrowing / Increase 1.000.000,00 +

24.08.2012 1200 Nominal interest 10.082,19- -

24.11.2012 1200 Nominal interest 10.082,19- -

24.02.2013 1200 Nominal interest 10.082,19- -

24.05.2013 1120 Final repayment 1.000.000,00- -

24.05.2013 1200 Nominal interest 9.753,42- -

I need the 1200 movements to be posted like this

D: Vendor Account

C: Bank Account

insgtead of

D: P&L  Interests

C: Bank Account

thenks in advance

CB