How do I make a GPRS connection using the stack?

AT#GPRSMODE=1 (sets the modem to GPRS mode)
AT#APNSERV="APN" (sets the APN for the modem to connect to)
AT#APNUN="<username>" (sets the APN username if needed)
AT#APNPW="<password>" (sets the APN password if needed)
AT+CGATT=1 (attaches the modem to the GPRS network)
AT#CONNECTIONSTART (to start the connection)
AT#CONNECTIONSTOP (to stop the connection)