I have had great success with iOS forcing the orientation to Landscape for quite a while. At least in Tier 2, it is easy.
// set a default resolution (for landscape iPhone)
agk::SetVirtualResolution(TA_GAM_WID,TA_GAM_HIH);
// set up for only one landscape
agk::SetOrientationAllowed(0,0,0,1);
// set to that orientation
agk::OrientationChanged(4);
I used the same basic Tier 1 commands, except for the OrientationChanged one, and it worked fine.
One of the keys is to remember to have the landscape orientation(s) as the only ones allowed in the Xcode project.
And, it doesn't hurt to manually edit the <projname>-Info.plist file to contain the following (if it doesn't already), the first one is the one that will force the orientation to where you want it:
<key>UIInterfaceOrientation</key>
<string>UIInterfaceOrientationLandscapeRight</string>
and
<key>UISupportedInterfaceOrientations</key>
<array>
<string>UIInterfaceOrientationLandscapeRight</string>
</array>
<key>UISupportedInterfaceOrientations~ipad</key>
<array>
<string>UIInterfaceOrientationLandscapeRight</string>
</array>
Of course, if you are allowing both landscape orientations, put the 'Left' version in the supported interface orientations section. And if you prefer the left landscape (the home button on the left) as the initial orientation, change 'Right' to 'Left' in the <string> field under <key>UIInterfaceOrientation</key>.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master