Symbolic link in /dev & NTP


I’m trying to use QNX platfom as a NTP server.

I install ntpd and execute it with a local clock as a time source. It works.
Then I tried to use GPS (Trimble Lassen SKII) receiver as a time source. To
use generic reference clock driver I need to create symbolic link (link to
serial port driver) /dev/refclock-0. So I can’t do it. System can’t create a
symbolic link in /dev.
Why? For example, Linux can to create symbolic links in /dev.