In the end, the most useful information came from Wikipedia which also stated that one could obtain the information I was asking for from the Motorola Dev website, which requires signing up for an account. Obtain this document if you want to delve into this subject in more detail.
I also got some hints from http://www.taniwha.org.uk/ which deals with interfacing these beasts to MacOS.
Anyway, I post below my wvdial script, which works. If you use a different dialer, you can easily see the AT commands you need to send.
[Dialer Defaults] Init1 = ATZ Init2 = AT&F0 Q0 V1 E1 S0=0 &C0 &D2 X1 X3 W1 S95=47 +CGATT=0 Init3 = AT+CGDCONT=1, "IP", "3netaccess" Modem Type = Generic Baud = 921600 New PPPD = yes Modem = /dev/ttyACM0 ISDN = 0 Phone = *99***1# Stupid Mode = true Carrier Check = no Abort on No Dialtone = off Username = a Password = a