[kronolith] "accept" vs "accept and add to my calendar"

[Calendar Debug]

Hello,

With Kronolith, when a potential attendee receives an email invitation 
from an event organizer, that email looks different in a regular MUA 
(Outlook, MacMail) than in Horde/Imp as it does not present the "accept 
and add to my calendar" option.

  Is there a way to have the same capability in the Outlook/MacMail?

It is my understanding that presently you cannot subscribe to Kronolith 
R/W from Apple Calendar without overwriting the already existing events. 
The above would enable MacMail users to accept the invitation and add 
the event directly from MacMail.

Or am I completely misunderstanding the way this should be done?!

Thank you!

Best regards,
Andrei