You don't really want to set the time directly from these messages....

You will have some jitter in your time messages _arrival_, and you
want to avoid backward jumps in the systems notion of time.

I think what you really want is to create a (pseudo-?) device which is
a stratum 0 time source for ntp, and let the ntp machinery smooth out
the jitter. Benefit of this is that the xntpd will adjust the system
clock even at times where you don't get time messages, and keep it at
the average clock speed it had measured during the times you had
messages.

You'll have to look at the xntpd distribution for examples for this... 

Regards,
	Ignatios Souvatzis