BuildPipeline for iOS 64 bit with il2cpp

How can I perform a BuildPipeline to output a iOS 64 bit Player?

I have code like this

BuildPipeline.BuildPlayer(
			new string[] {
			"Assets/scenes/intro/SceneIntro.unity", // The scenes to be included in the build. If empty, the currently open scene will be built. Paths are relative to the project folder (Assets/MyLevels/MyScene.unity).
			"Assets/scenes/codestarter/SceneCodestarter.unity",
			"Assets/scenes/title/SceneTitle.unity",
			"Assets/scenes/game/SceneGame.unity",
			"Assets/scenes/help/SceneHelp.unity",
			"Assets/scenes/ranking/SceneRanking.unity",
			"Assets/scenes/setup/SceneSetup.unity",
		},
		exportpath, // The path where the application will be built.
		BuildTarget.iPhone, // The BuildTarget to build.
		BUILDOPTIONS // Additional BuildOptions, like whether to run the built player.
		);

Where BUILDOPTIONS is defined like this:

const BuildOptions BUILDOPTIONS = BuildOptions.Il2CPP;

However this seems to generate plain old mono code. Also, how can I select architectures (universal, both arm7 and arm64 needed)??

You will likely need to set the ScriptingBackend and Architecture properties in the player settings. See this forum post for more details:

http://forum.unity3d.com/threads/4-6-ios-64-bit-beta.290551/page-9#post-1948394