UDO Master and Detail Add/Row update

hi,

How do I programmatically insert and update UDO without using SAPB1 default Add/Update which is assigning uniqueID=1?

I can insert into detail rows successfully such as described below.

UDT = oCompany.UserTables.Item("TB_QSCORE");

UDT.Code = "1";

UDT.Name = "Hello";

UDT.UserFields.Fields.Item("U_SCORE").Value=2;

UDT.UserFields.Fields.Item("U_LONGDES").Value="SAMPLE ";

int iErrcode=UDT.Add();

But I cant insert successfully in master row data. Can anyone suggest how to do this?

Thanks,