If these are purchased, from the iTunes store, then the h320 will not play them.
However if they are AAC, and not purchased, export them as MP3 and then move them onto the h320.
If they are already MP3 and you have moved them onto the h320 and still cannot hear them, I would suspect the h320 of having a problem.
You probably cannot just drag them from the iTunes Library. The tracks would probably have to exist outside of the Library to be able to move them.