GSM device in virtual serial port via USB

[Vieri]

Hi,

I'm using an RS-232 to USB adapter to connect my GSM trac to my server via USB.

So in gnokiirc, my GSM trac configuration is:

[phone_usb0]
port = /dev/ttyUSB0
model = AT
initlength = default
connection = serial
use_locking = yes
serial_baudrate = 115200
serial_write_usleep = 5000
handshake = hardware
smsc_timeout = 60

All's fine until I eventually need to switch the GSM trac off and back on again 
for whatever reason (eg. power failure, GSM device hardware not responding 
anymore, etc.).

Unfortunately, switching the device off and back on again makes it's virtual 
port go from ttyUSB0 to ttyUSB1. So I need to manually unplug the USB cable and 
re-plug it in to get it assigned again to ttyUSB0.

How can I avoid this manual intervention (either LinuxOS-wise or Gnokii-wise)?

Here are the last lines of my dmesg:

usb 2-2: USB disconnect, address 4
ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
ftdi_sio 2-2:1.0: device disconnected
usb 2-2: new full speed USB device using uhci_hcd and address 5
usb 2-2: configuration #1 chosen from 1 choice
ftdi_sio 2-2:1.0: FTDI USB Serial Device converter detected
drivers/usb/serial/ftdi_sio.c: Detected FT232BM
usb 2-2: FTDI USB Serial Device converter now attached to ttyUSB0
hub 2-0:1.0: port 2 disabled by hub (EMI?), re-enabling...
usb 2-2: USB disconnect, address 5
ftdi_sio 2-2:1.0: device disconnected
usb 2-2: new full speed USB device using uhci_hcd and address 6
usb 2-2: configuration #1 chosen from 1 choice
ftdi_sio 2-2:1.0: FTDI USB Serial Device converter detected
drivers/usb/serial/ftdi_sio.c: Detected FT232BM
usb 2-2: FTDI USB Serial Device converter now attached to ttyUSB1
drivers/usb/serial/ftdi_sio.c: error from flowcontrol urb
drivers/usb/serial/ftdi_sio.c: update_mctrl Error from MODEM_CTRL urb: DTR LOW, 
RTS LOW
ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
usb 2-2: USB disconnect, address 6
ftdi_sio ttyUSB1: FTDI USB Serial Device converter now disconnected from ttyUSB1
ftdi_sio 2-2:1.0: device disconnected
usb 2-2: new full speed USB device using uhci_hcd and address 7
usb 2-2: configuration #1 chosen from 1 choice
ftdi_sio 2-2:1.0: FTDI USB Serial Device converter detected
drivers/usb/serial/ftdi_sio.c: Detected FT232BM
usb 2-2: FTDI USB Serial Device converter now attached to ttyUSB0

Thanks,

Vieri