Metodo MethodBuilder.SetMarshal

	MethodBuilder myMethod = myDynamicType.DefineMethod("MyMethodReturnsMarshal",
						MethodAttributes.Public,
						typeof(uint),
						new Type[] { typeof(string) });

	// We want the return value of our dynamic method to be marshalled as 
	// an 64-bit (8-byte) signed integer, instead of the default 32-bit
   	// unsigned int as specified above. The UnmanagedMarshal class can perform
	// the type conversion.

	UnmanagedMarshal marshalMeAsI8 = UnmanagedMarshal.DefineUnmanagedMarshal(
				         System.Runtime.InteropServices.UnmanagedType.I8);	

	myMethod.SetMarshal(marshalMeAsI8);