Comment 4 for bug 76347

give wvdialconf a chance, maybe it can find the modem:
https://help.ubuntu.com/community/DialupModemHowto/SetUpDialer#head-277fdde88a3b04feee00e14834388d58d7add4f9

other than that, I won't be able to help sorry. you might wanna try ubuntuforums.org for more help (maybe someone else is using it as well?)...