How to get/set iOS camera properties using U3DXT?

I'd like to access the SDK's camera properties for an iOS device. In Apple's Objective-C documentation below, it seems fairly straightforward if I were building my app in Xcode. But since I'm working in C# in Unity, I'm not sure how to access those methods.

https://developer.apple.com/library/prerelease/ios/documentation/AVFoundation/Reference/AVCaptureDevice_Class/index.html#//apple_ref/doc/uid/TP40009520-CH1-SW4

For example, if I wanted to change the exposure mode and read when the camera is focusing, in Objective-C, there is the exposureMode and adjustingFocus properties for a AVCaptureDevice. However, I couldn't find the equivalent documentation in the U3DXT API.

I'm using Unity 4 Pro and iOS SDK Pro on Yosemite.