export / import problem with Outlook

If you want to transfer an appointment from ‘Event Calendar’ to Outlook (2013), a completely new calendar will be imported / created on my system for each exported appointment. Very annoying! It would be better, it is made a new entry in the standard calendar of the user.
If you add the line “X-MS-OLK-FORCEINSPECTOROPEN: TRUE” to the exported file, a single appointment will be imported in OL. If the line is missing (as with the file of ‘Event Calendar’), then a new calendar will be created with the new appointment.
However, I do not know if the compatibility e.g. to Apple is guaranteed if the MS-OLK line is in the file ….. It would be great if this functionality could be produced!
JMB