network-admin not working for my dialup

[Lex Hider]

Having set up the details for ppp in network-admin [i.e. "system
configuration"->Networking] it won't connect.
When I try to activate it the tick-box in the active column is ticked
for about a second that is clears. 
The modem doesn't respond in anyway it doesn't even check for a
dialtone.

So I am know connected via pppconfig/pon which is working fine.

I really have no idea what the problem is but I would guess it could be
a problem with detecting my modem. My modem is a NetComm Wave SP56.
pppconfig fails to autodetect this modem and I have to manually
specify /dev/ttyS1 as the modem port.

Lex.