RowFilter in child table

[Kartic]

Hi,
I have a dataset(dspo) with two tables Inventory(Parent) and
Locations(child)

I have added a relation between thest two tables
dsPO.Relations.Add("Inventory2Locations",
dsPO.Tables("Inventory").Columns("InventoryID"),
dsPO.Tables("Locations").Columns("InventoryID"))

I filtered Inventory table for cost>0
dsPO.Tables("Inventory").DefaultView.RowFilter = "Cost>0"

and assign to a datagrid
grdDetails.DataSource = dsPO.Tables("Inventory").DefaultView

My question is is there any way filtering child rows. I want to filter for
OrderCode='s' in Location table. When I put .
dspo.Tables("Locations").DefaultView.RowFilter ="OrderCode='s'"
Datagrid doesn't change or filter child rows.

Thanks for your help,
Kartic