Hi Rajendra,
I think you can use the Multiplier, but you need to Personalize the page.
Go to the Data Exchange Definition, Line Definition, Manage, Field Mapping.
The "Multiplier" field is not visible, but available, and you need to Personalize the Page:

You click on the ribbon on the +Field:

Then you can see the Multiplier field in the list (put the cursor over the LINES), and you can add it:

Then you can use it normally , and put it as -1 to get a negative amount:

I hope it helps,