you can try attaching the editor attribute like the oledbcommand object's
commandtext property, note, it is under a VSDesigner assembly...

[Editor("Microsoft.VSDesigner.Data.ADO.Design.OleDbCommandTextEditor,
Microsoft.VSDesigner, Version=7.0.5000.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor)),
RefreshProperties(RefreshProperties.All), DataCategory("DataCategory_Data"),
DefaultValue(""), DataSysDescription("DbCommand_CommandText")]
public string CommandText
{
     get
     {
           if (this.cmdText == null)
           {
                 return string.Empty;
           }
           return this.cmdText;
     }
     set
     {
           if (ADP.SrcCompare(this.cmdText, value) != 0)
           {
                 this.OnSchemaChanging();
                 this.cmdText = value;
           }
     }
}