新增凭证时带核算项目，怎么写

下面是我测试程式新增凭证的代码，但是我要针对贷方客户1002增加核算项目，要怎么写，请问有谁教教我啊？谢谢
"{
"Creator": "Demo",
"NeedUpDateFields": [
""
],
"Model": {
"FVOUCHERID": 0,
"FAccountBookID": {
"FNumber": "006"
},
"FDate": "2014-8-8",
"FYEAR": "2014",
"FPERIOD": "8",
"FBILLNO": "30",
"FVOUCHERGROUPID": {
"FNumber": "PRE001"
},
"FVOUCHERGROUPNO": "30",
"FATTACHMENTS": "0",
"FBASECURRENCYID": {
"FNumber": "PRE001"
},
"FDEBITTOTAL": "100.00",
"FCREDITTOTAL": "100.00",
"FCreatorId": {
"FUserAccount": "100007"
},
"FCreateDate": "2016/3/14 17:31:44",
"FDocumentStatus": "A",
"FACCTORGID": {
"FNumber": "101.2"
},
"FEntity": [
{
"FEXPLANATION": "Test",
"FACCOUNTID": {
"FNumber": "1001"
},
"FAMOUNTFOR": "100.00",
"FAMOUNT": "100.00",
"FCURRENCYID": {
"FNumber": "PRE001"
},
"FEXCHANGERATE": "1.00000",
"FDC": "1",
"FDEBIT": "100.00",
"FCREDIT": "0.00",
},
{
"FEXPLANATION": "Test",
"FACCOUNTID": {
"FNumber": "1002"
},
"FAMOUNTFOR": "100.00",
"FAMOUNT": "100.00",
"FCURRENCYID": {
"FNumber": "PRE001"
},
"FEXCHANGERATE": "1.00000",
"FDC": "-1",
"FDEBIT": "0.00",
"FCREDIT": "100.00",
}
]
}
}"