Cannot get my Samsung SyncMaster S27B370 to connect to my Mid 2011 iMac 27

Cannot get my Samsung SyncMaster S27B370 to connect to my Mid 2011 iMac 27 inch with HDMI to thunderbolt port adapter but works like a charm in Windows 7 when I bootcamp over to it. Any ideas? The cable is working properly as shown by the fact that Windows 7 uses both monitors perfectly. I am using Mac OS X Mountain Lion and have already done the option + cmd + p + r boot reset to no avail. It does not find the second monitor at all as in it doesn't even show up in the display preference pane.