POSTING_INTERFACE_CLEARING Tax line item

Hello Experts,

I am using FM POSTING_INTERFACE_CLEARING  for clearing documents and everything working fine but there is one new requirement where client want to post tax line item as well, is anybody know how can i achieve this ?

I have checked FM and there is one internal table for TAX calculation which is T_FTTAX , let me know how can i use this table, please provide me some sample code. 

Waiting for response.

Thanks.

Regards,

Nee