Add TaxCode DI API Of Inventory Transfer

Hi Experts,

I have this DI API of Inventory Transfer. I'm having a trouble on tax code. I have an error like this

"Public member 'VatGroup' on type 'IStockTransfer_Lines' not found."

When I remove the oST.Lines.VatGroup = "IV-0-SCM" it works fine.. I need to add a tax code . how can I achieve it?

Here's my code:

Dim oST As SAPbobsCOM.StockTransfer = oCompany.GetBusinessObject(SAPbobsCOM.BoObjectTypes.oStockTransfer)

        Dim serrmess As String = ""

        Dim errorid As Integer

        Dim retval As Integer

        If (Not oCompany.InTransaction) Then

            oCompany.StartTransaction()

            oST.CardCode = "C-0000005"

            oST.DocDate = "02/12/16"

            oST.TaxDate = "02/12/16"

            oST.FromWarehouse = "S-LAF-CA"

            oST.ToWarehouse = "S-LAF-BU"

            oST.Lines.ItemCode = "A-00000002"

            oST.Lines.Quantity = 10

            oST.Lines.Price = 1

            oST.Lines.WarehouseCode = "S-LAF-BU"

            oST.Lines.VatGroup = "IV-0-SCM"

            oST.Lines.Add()

            retval = oST.Add()

            If (retval) Then

                oCompany.GetLastError(errorid, serrmess)

                MsgBox(serrmess)

            Else

                MsgBox("Added")

                oCompany.EndTransaction(SAPbobsCOM.BoWfTransOpt.wf_Commit)

            End If

        End If