How can I set the visibility of an ActionBar item in different fragment

I'm looking for a way to set the visibility of a MenuItem inflated in my MainActivity depending on which Fragment I am on.

For information: I'm using actionBarSherlock, zxing, and some google services.

The application was built with a Navigation drawer(With abs), also I manipulate the FragmentStack in such way I everytime I switch to another Fragment when I press the touch back I come back in my Main Fragment.

Here my menu:

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
   <item android:id="@+id/button_generator" android:title="GENERER" android:icon="@drawable/ic_drawer"></item>
</menu>

Here is where I inflate the menu:

 @Override
public boolean onCreateOptionsMenu(Menu menu) {
    Log.d(TAG, "================= onCreateOptionsMenu ================= fragSt: " + fragmentStatus);
    this.getSherlock().getMenuInflater().inflate(R.menu.main, menu);

    mGenQrFromContacts = menu.findItem(R.id.button_generator);


    return true;
}

I've tried the solution purposed here, but ain't work in my case.