Facebook API: Check In to an Event?

I can't find any information about event checkins. Facebook do this in their application and I want to allow users to do the same within my application:

• How do I checkin a user to a Facebook event?

• How do I retrieve all of the us开发者_如何学编程ers checked into an event?

I have tried replacing the 'place id' with an 'event id', which didn't work. I don't know what to try or what will work. Can anyone help?

   eid = 327125807317374;
   location = "bla bla";
   name = cars;
   "start_time" = 1324166400;
   venue =         {
       city = "";
       country = "";
       id = 207275525951980;
       latitude = "-6.17151";
       longitude = "106.82774";
       state = "";
       street = "";
   }; 

the event has a venue object. inside this is an id which (sometimes) corresponds to a place. Use this place id to check in.

You can't check in to an event or retrieve checked in users from an event.

Not exaclty, that will checkin on the Place, not the Event.