No datakey options when using stored procedure

[Matthew]

Hi all,
I am using the radgrid with data that must be accessed using SQL stored procedures.
I have created the SQLDataSource and assigned all the required sp's and their parameters.

My select statement *does* select a unique PK for the dataset

However, when I bind the radgrid to the SDS there are no options to select in the "Data key name(s)" field in the grid property builder.
Is there a trick to getting them to show up here?

I have loosely followed the guide here:
http://www.telerik.com/community/code-library/aspnet-ajax/grid/update-insert-delete-with-stored-procedures-and-sqldatasource-control.aspx

But still I get no options for datakeys

Is there a silver bullet here? Some setting I may have incorrectly applied?

Thanks

[Matthew]

I have resolved the issue.

I can manually type in the value and it works.
However, the name of the value must match the column name in the child row and the parameter name for the stored procedure.