In Depth details regarding Internal order creation

Hi Friends,

I know what is internal order and for what it is used for. I am able to create internal order also.

After creating internal order i am going to Tcode FB50 and then assigned few line items where debit should be equal to Credit..

Then i am going to f-02 and then gave 'post with reference' and then specified few line items and then it is posted to particular company code.

But when i go to KO88 and try to settle its showing 'Its either settled or nothig yet to settle' .

I donno where i am going wrong..

Please help me on this regard

Thanks in advance

kishore