Note the time of the meeting in the email. Then launch Corporate Calendar and the event will be on your calendar, but not as accepted. Click the meeting and you can act on it from the calendar itself.
the Exchange integration could be a lot better, but they are making small steps with the first hotfix. hopefully we'll see more and more integration over time.
The calendar invites look just like regular email. It is a pain to manually go into the calendar and accept. How could they overlook such an important detail?
The January update is supposed to correct a lot of the exchange issues. Yes it is important but not all the world is on Microsoft. In the meantime there are workarounds mentioned above, or you could grab touchdown from the app store. It does it all. Try it free for 5 days to make sure.