IME(Input Method Editor) Chinese Pin yin

Hi, currently i have a NGUI inputfield and I am using the windows 7 built in IME to type my chinese.

Basically i want to be able to customize the position of this IME suggestion box. But seems impossible, so the workaround is

Unity3d read Inputfield text>send to plugin>using the plugin> Get output from IME>send this to Unity>Unity saves in array. Any possibilities of this?

I have tried referencing to this http://www.kumei.ne.jp/c_lang/sdk3/sdk_282.htm (translated to english) to get some idea.

As i create the plugin, I am stuck when i try to reference to PresentationCore.dll in my plugin. Apparently unity3d does not support this due to it being multiplatform(and Net 2.0)?http://answers.unity3d.com/questions/137245/reference-to-systemwindowsinput.html

I am not sure of any ways to implement this. Any ideas would be helpful. Thank you