Note that when a Custom value is used for this property, it is also necessary to use the CustomFormatString property; this is done in order to set the string that will contain the date & time symbols.
You can refer to the example below to see how this can look in your code.
Target Platforms: Windows 11, Windows 10, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2