Why can't I accept mail invites in iCal sent to Mail?

Ok I'm sure there is an easy answer...this is driving me batty...

I get lots of iCal invites that are sent to my email address.

When I open iCal, very few of them appear in the "Notifications" area to allow me to say Maybe/Decline/Accept

The way I have to accept most of them is to:

1. go to email for the invite

2. click "Accept" (opens a new browser tab)

3. within browser tab click on "Download .ics" (Add to iCal), which opens a download window

4. in download window select "Open with... iCal"

5. asks which calendar I want to add it to (like "Home"), so I hit OK

then it adds it to my iCal

I get tons of iCal invites...is there a way just to let me just accept them from within iCal?

I don't have a Cloud subscription of anything (if that matters).

Thanks all-