'+' not supported in datakey

Users reported us that sometimes the selection is lost in UltraWebGrid. We managed to discover that the problem occurs only when the key column contains '+'. The selection is recognized OK on client side, but on server side it behaves as if the selected row was the one without '+', i.e. none if there was no such row.

Having the data source

    [DataObject]
    public class DataProvider
    {
        [DataObjectMethod(DataObjectMethodType.Select)]
        public static IEnumerable SelectData()
        {
            yield return new { Column1 = "a+b" };
            yield return new { Column1 = "a b" };
        }
    }

and the grid

<igtbl:UltraWebGrid ID="UltraWebGrid1" runat="server" DataSourceID="ObjectDataSource1">
            <Bands>
                <igtbl:UltraGridBand DataKeyField="Column1">
                    <Columns>
                        <igtbl:UltraGridColumn Key="Column1" BaseColumnName="Column1" IsBound="True"></igtbl:UltraGridColumn>
                    </Columns>
                </igtbl:UltraGridBand>
            </Bands>
            <DisplayLayout …>…</DisplayLayout>
</igtbl:UltraWebGrid>

you can select the row with "a+b", but once you enter server code (e.g. for server event handling), the selection is changed to "a b".

We needed to introduce another column to store the key value with '+' escaped somehow (e.g. replaced for another character).

Updated 3 February 2010:
I have been told by a colleague that even server events are not raised for a row having '+' in its key.