Plextor has chosen to limit the use of certain functions of its drives to Plextools only, as is explained here: http://club.cdfreaks.com/showthread.php?t=160680 .
As it turned out, even Bitsetting was among those functions initially. As for the PX-755, beginning with FW 1.02 bitsetting has been made available to every software again (and works with Nero 126.96.36.199).
FW 1.02 for the PX-755 corresponds to FW 1.01 for the PX-760. 1.01 is only a few days old. Is your friends PX-760 still running FW 1.00?