How to cancel Sales Order in AX2009 using .Net webservice

I added reference of 'SalesSalesOrderService' AIF webservice in .Net, and now I want to cancel a SalesOrder Record in Dynamics AX 2009. 

I tried by setting 'Service.SalesStatus' to 'Cancelled'. It is compling fine, but not getting proper output in AX.
I know, we can cancel by setting 'Deliver Remainder' to Zero, but I am not able to do the same by .Net.