Harmonics scoring for strings.

When indicating artificial harmonics in the strings, a diamond shaped note head is placed a perfect 4th above the pitch indicated to produce the desired sound harmonic two octaves above the written pitch. This diamond shaped note head is supposed to be "open" no matter what the value of the lower pitch. However, I cannot get the diamond shaped note head to be "open" when I place it above a "closed" note (i.e. quarter note or less). It always takes on the same open or closed characteristic as the note below it. Is this a problem with the software am I just not doing it right? Also, when I play back the section with harmonics, the sound does not reproduce the harmonic, just the main note "as written," which is annoying. Is there a fix for that as well.