how to create virtual serial port device on QNX4.25

[davesliu]

Hello,
I can use Dev.Ser command with -n option to "mount" and rename serial port device under /dev fold of QNX.45 such as /dev/virtual_serial_port.

Is there any way that can create virtual serial port device on QNX4.25?
I've tried to use open("/dev/virtual_serial_port", ...) with creation option, but it can't create virtual serail_port under /dev foler.
How can I create a virtual device drive on /dev folder ?