my hayes usb does not always work on boot

hi!

    i have a usb modem Hayes V.92, Series 0375. I'm using Debian 4.0 
(Etch), with kernel 2.6.19.7. I successfully installed the hsf driver, 
and the modem does work. But, i have this problem: if i turn off the pc, 
the modem doesn't work after boot. If the modem is not working, and I 
unplug the modem, and plug it again, it's recognized and works. If the 
modem is working, and I reboot without cycling power, then it continues 
working after boot. What could i do for the modem to work without the 
plug / unplug move?


    tia,
    René