Fill dataset table

I have a dataset that I have created earlier like this:

Public Sub Main()
    dim ds as dataset
    ds  = buildDS()
    getCars(ByVal ds As DataSet)
End Sub

Private Function buildDS() As DataSet
        Dim ds As DataSet = New DataSet("DS")
        ds.Tables.Add(CreateCarTable)
        Return ds
End Function

Private Function CreateCarTable() As DataTable
        Dim dt As DataTable = New DataTable("Cars")
        dt.Columns.Add(New DataColumn("Manufacturer", GetType(String)))
        dt.Columns.Add(New DataColumn("Model", GetType(String)))
        Return dt
End Function

I call a function that executes SQL for me and it adds the data to the dataset  --> ds.tables(0), but I want to copy the data to the datasets table I created earlier. -->   ds.tables("Cars")  
How can I make sure this select statement goes into the table, ds.tables("Cars"), that I created earlier and not just to ds.tables(0) ??

        Public Function getCars(ByVal ds As DataSet)
            Dim sSQL As String = "SELECT MANUFACTURER, MODEL FROM CARS"
            ds = OracleHelper.ExecuteDataset(AppSettings.ConnectionString, CommandType.Text, sSQL, Nothing)
            return ds
        End Function

Thanks for your time