arcobjects - Add-In button Click open ArcCatalog window with list of .sde files

I want code to open ArcCatalog window with list of .sde files.The below code always opens an ArcCatalog window with home location. I have to go to database connections from the window which finally gives me list of .sde files. I want code to show list of .sde files directly on click on Add-In button instead of going to multiple selection options in the window and finally listing the .sde files.

                IGxDialog gxd = new GxDialogClass();
                gxd.AllowMultiSelect = false;
                gxd.ButtonCaption = "Add";                
                gxd.RememberLocation = false;

                IGxObjectFilter gxObjectFilter = new GxFilterDefaultDatabaseWorkspaces();
                gxd.ObjectFilter = gxObjectFilter;

                IEnumGxObject gxEnumObj;

                gxd.DoModalOpen(ArcMap.Application.hWnd, out gxEnumObj);