about virtual usb-serial converter

can anybody help me out.i’m trying to write a virtual
usb-serial converter driver i.e. virtual usb-serial comm port on
QNX.i’m having usb-ddk & ser-ddk.which one will be helpful for
me.i’m bit confused that i’ve to write a new resource manager or
write using this kit.

if anyone have tried for this please help me out.