Populating a COMBO within a grid using the .net connector

I have followed the instructions as outlined in this document… but can’t get the a combo embeded in a grid using the .net connector to work.

docs.dhtmlx.com/doku.php?id=dhtm … _with_data

On the server I have

dhtmlxGridConnector thisConnector = new dhtmlxGridConnector(“SELECT …”,dhtmlxDatabaseAdapterType.SqlServer2005, connectionString);

thisConnector.ExplicitOptions.Add((TableField)“[ENTITY]”, “Value1”, “Value1”, “Value3”);

On the calling page I have set the column to “coro” and it does show a read only column. It shows the default value but the drop down is always blank.

I have also tried:
thisConnector.ExplicitOptions.Add(thisConnector.Request.RequestedFields[0], “Extension”,“Alpha”, “Beta”, “Gamma”);
but get the same results.

Am I missing something here. Shouldn’t the above populate my combo with default values?