Formatting Childgrid inside Master Grid

[Eclipse414]

Hello Guys, here is what i am trying to do...i am trying to add some rows(subheading rows) to the child grid inside the master datagrid and not sure where to do it...

i have filled my datasets as below for master and child grids

oDA.Fill(oDataSet, "items")
        oDA.SelectCommand.CommandText = sql2
        oDA.Fill(oDataSet, "itemdetails")

here is the relationship

Dim rel As New DataRelation("payrecord", _
        oDataSet.Tables("items").Columns("Item_No"), _
        oDataSet.Tables("itemdetails").Columns("Item_No"))
        oDataSet.Relations.Add(rel)

here is the sub to bind child grids

Sub BindItemDetails(ByVal sender As Object, ByVal e As DataGridItemEventArgs)
        Dim oType As ListItemType = CType(e.Item.ItemType, ListItemType)
        If oType = ListItemType.Item Or oType = ListItemType.AlternatingItem Then
            Dim oGrid As DataGrid = CType(e.Item.FindControl("dgr2"), DataGrid)

            Dim skey As String = dgr1.DataKeys(e.Item.ItemIndex)
            Dim oView, oChildView As DataView

            oView = oDataSet.Tables("items").DefaultView
            oView.RowFilter = "Item_No='" & skey & "'"

            oChildView = oView(0).CreateChildView(oDataSet.Relations("payrecord"))

            oGrid.DataSource = oChildView
            oGrid.DataBind()
        End If
    End Sub

works fine...but as i said i need to insert somerows to the childgrid which i am not sure where to do...

thanks