Microsoft Dynamics Axapta Technical,Functional Coverage

How to generate sales Order number in axapta by code NumberSeq           num;  SalesTable salesTable; ; num = NumberSeq::newGetNum(SalesParameters::numRefSalesId()); salesTable.SalesId = num.num();  if (salesTable::exist(salesTable.SalesId))    {           num.abort();          checkFailed("@LIQ1977");           checkFailed(strfmt("@LIQ1978", salesTable.SalesId));           throw error("@SYS23020");         }                            num.used();