The iControl proxy for EM will be a true proxy to the LTMs. You will configure your iControl client to point to the EM device and by using the methods in the iControl.Management.EM interface, you can tell EM which device you would like to be connected to. Then all further iControl calls you make to the EM will be sent on to the selected LTM device. I believe I updated all the assemblies with these new methods in the latest iControl 11.1 assemblies. So, when you have a EM setup with the proxy, you should be able to use the latest libraries to make use of the proxy.
-Joe