If you are using MonoTouch 4.0 and the assembly does not reference monotouch.dll (directly or indirectly), you just need to reference the assembly from the Mono project for Android.
Please note that at this time you can only reference the assembly ( .dll ) and not the project ( .csproj ).
The converse should also be true (refer to the Mono build for Android and use MonoTouch in your project until the Mono build for Android references Mono.Android.dll ).
If this breaks down, write a mistake: we are fully committed to supporting MonoTouch and Mono compatibility for the Android API. (If possible, things like System.Reflection.Emit will never be supported on both platforms unless / until Apple removes the JIT restriction.)
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