The initscripts should support demand dialing for ppp
connections (in particular, if you select demand dialing,
the ifup sequence will delete the /var/run/ppp-<iface>.dev
file when run, and when the ppp chat session is eventually
called, it doesn't use the appropriate device to dial out
on). Given that you rejected my previous bug asking that
diald be supported because of demand dialing, I think you
should really support it then.
Our current setup will support demand dialing by add the word demand
to the ppp-options list. You can do this using Linuxconf or netcfg.
Try this and reopen the bug with the description of what
/var/log/messages is reporting after you try to bring up the interface
and then access a network function.