I am trying to monitor the Google Analytics request on an iPhone application and for some reason I don\'t see any of GA the requests. However I can see and uniquely identify
The problem is that the tracking calls that the Google Analytics SDK makes are not using the iOS HTTP proxy.
If GA tracking calls doesn't use the iOS proxy they obviously won't be sent to Charles (or Fiddler or whatever) and it can't track anything. The only way to monitor these calls is to do something like share your ethernet internet connection on your computer to your iOS device wirelessly and use a tool like ngrep or WireShark to monitor the traffic coming through your wireless interface (usually en1 on a Mac). Here's an example ngrep command:
sudo ngrep -d en1 port 80 | grep --color -E -C 3 '(google|utm.gif)'
(You can easily install ngrep via homebrew on a Mac)
Or with Wireshark you can start monitoring your wireless interface (en1 on a Mac) and type "http" into the "Filter:" box to filter down to http traffic.
If you have the source code for the app then another option to avoid 'internet connection sharing' is to run the app via the iOS Simulator in Xcode on your Mac so that it uses your Mac's internet connection. The GA code actually still refuses to use the OSX-configured proxy (i.e., you still can't use Charles) but you can then use ngrep or Wireshark (as above) on your Mac without having to set up internet connection sharing.
Here's a post on my blog with more details: Monitoring Google Analytics for iOS