objective-c method call from unity

Hi, I'm trying to call an objective-c method from unity using C#. I'm using the plug-in method described here. I can get this method to work if I include my header and mm files directly in the Unity generated Xcode project but, what I'm trying to do is create a static library or even a framework with my interface and implementations defined in those but I get an error that my referenced methods are not defined, which happens if I don't even include my .h or .mm files. My problem may be that I'm not creating a framework or a static library correctly (which I suspect is my problem). Now, my question is: can I even use dllimport in this manner, such as calling a function defined in a static or dynamic xcode library? Thanks in advance.