control line items when payment document posted

Hi,

I need to control the line items which are cleared when particular type of payment document is posted. For example document type ‘XX’.

For this purpose I have attached custom FM in clearing variant which is copy of standard FM - FKK_SAMPLE_TFK115.

My requirement is when I have payment document type XX.

• This payment should not clear document type SD
• This payment should clear only those open amount which have main/sub as 9000/0010

Can anyone tell me what all things in this custom FM we have to use in order to control which item should be cleared and which should not.

Thanks,

Ravi.