USB - Serial converter module woes

Hello.

I am trying to get gpsdrive running on my laptop using a Knoppix 5.0.1
CD but with no serial ports I need to use a USB - Serial converter to
connect the gps unit to it.

I have a *** Smith Electronics XH6381 (New Zealand version) converter
which is known to work OK using a different OS. It is based on a ftdi
chipset so I thought the ftdi_sio module should work. When I plug it in
lsusb shows it as:

Bus 004 Device 003: ID 0b39:0431 Omnidirectional Control Technology, Inc.

It just sits there but no kernel module loads and no device (ttyUSB0?) is
allocated for it.

Looking through the code for the ftdi_sio module I see that it is looking
for a product code of 0421 and my converter says it is product code 0431.
There doesn't appear to be an option to pass the vendor and product codes
to the module.

Is there some way to force the ftdi_sio module to use my converter without
having to hack the source code and recompile?

Thanks,

Graham
.