How to get the net invoice amount

Hi Friends,

There is the requirement to get the net invoice amount i.e. Invoice amount - Partial payment.

Suppose invoice is of Rs. 1000 and partial payment 450. So it will show only the net invoice value 650.

Because when I am sorting it, it is showing the invoice document and clearing document as well. So if somebody can tell how to get the net balance showing in the invoice.

With regards

Anand