AirPlay mirroring

[jobberone]

iMac with Mtn Lion and 2nd gen AppleTV. I have the AppleTV set properly. Both on wireless same network. I don't see the AirPlay icon on my iMac bar. I do see it on iTunes. I don't know what I can stream. Can't do HBOGo or ABC.com. Need some help, please. Thanks.

 

[Meat-O-Rama]

iMac with Mtn Lion and 2nd gen AppleTV. I have the AppleTV set properly. Both on wireless same network. I don't see the AirPlay icon on my iMac bar. I do see it on iTunes. I don't know what I can stream. Can't do HBOGo or ABC.com. Need some help, please. Thanks.

Won't work with older generation iMacs. I have the same problem.