In 4D 2004.2 there is now an option to specify a shortcut to a Menu Item where the shortcut can contain the shift key. To enable the shift key for a Menu Item, open the Toolbox in Design Mode, enter the Menus section, and select the Menu Item. Then check the option "Shift". After refreshing the Menus in Custom Menus Mode, you'll then notice the Shift modifier as part of the shortcut for that Menu Item.