How do you log in? The preferred secure method is ssh, which also does X forwarding for you. Depending on your ssh configuration, you may need specify "-X", but often it's enabled by default. If the client was, e.g., xclock, you'd say
Code:
ssh -X hpuxhost /usr/X11R6/bin/xclock
That's the easiest. You could also send over the DISPLAY and the X authentication cookie, essentially automating what you're doing by hand.
Good luck!