ILOG CP optimizer: iostream.h not found?

I was trying IBM ILOG CP optimizer C++ API but found this error (Visual Studio 2010):

error C1083: Cannot open include file: ‘iostream.h’: No such file or directory

The error was located in ilosys.h and for a few seconds I thought I had to edit all the library .h files!!!

Fortunately I discovered it’s not necessary, simply

#define IL_STD

and things will work smoothly.