asterisk users - Apr 2005 - Establish a ppp connection with a Pipeline 50

Hello,
I'm trying to get asterisk to use a data channel to establish a ppp
connection to a Pipeline 50 ISDN router.   Basically, I'm using the
outgoing spool directory of * with a call file and then passing that
call to the ZapRas command.  I'm kind of lost though because of lack
of documentation on the subject (and digium support for that matter). 
Does anyone know how to establish a digital ppp connection through * ?

Thanks,

Jason