wpf GridView column which is implemented a cell template sort by

hi there

How can I sort a wpf GridView  column which is implemented a cell template
Eg

<GridViewColumn Header="Order_no" DisplayMemberBinding="{Binding Path=Order_no.DataValue}" />

<GridViewColumn Header="Organisation"   DisplayMemberBinding="{Binding Path=Organisation.DataValue}">
<GridViewColumn.CellTemplate>
 <DataTemplate>
  <TextBlock Text="{Binding Path=Organisation.DataValue}">
  <TextBlock.ToolTip>
  <TextBlock Text="{Binding  Path=Organisation.DataValue}"/>                                                      
 </TextBlock.ToolTip>
  </TextBlock>
      </DataTemplate>
 </GridViewColumn.CellTemplate>
 </GridViewColumn>

IN THE Above grid I can sort the grid by order_no but not by Organisation how can I make to sort even if its implemented cell Template
Thanks