Automating PPP connection: adding the insertion in routing table of the new interface

I start my USB 3G Modem by:

# wvdial

And then I must do, in order to acquire internet access:

# route add default ppp0

Note that ppp0 is, in this case, the newly created virtual network interface.

I would like to automate this:

#!/bin/bash 
wvdial
route add default ppp0

But sometimes there is some previous ppp connection established (i.e: VPN), so the correct adapter must have another number (it is created as ppp1, ppp2... etc), and I need to parse ifconfig output or any other method.

Isn't there a more practical way to automate the routing part of the PPP connection?

EDIT-1: This is my /etc/wvdial.conf :

[Dialer Defaults]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init3 = AT+CGDCONT=1,"IP","ac.vodafone.es";
Modem = /dev/ttyUSB0
Phone = *99***1#
Username = vodafone
Password = vodafone
Stupid Mode = 1
# Carrier Check = no
#Dial Command = ATDT
#Baud = 9600
Baud = 460800
ISDN = 0
Modem Type = Analog Modem

The carrier is Vodafone.

EDIT-2: My distro is Kali Linux v1.0.5

EDIT-3: Added to /etc/wvdial.conf :

New PPPD = yes

Still no results :-( .