[Xastir] Xastir doesn't recognize the GPS serial port

[Menga]

This is a question related to Linux more than to Xastir.
My GPS device ha a special serial/USB converter so that the system see it in 
the dev/serial as ttyACM0.
On windows I have to run a script provided by the developer .inf as a 
driver.
Linux sees the device as a serial port, but Xastir with port configurated as 
ttyACM0 doesn't receive the NMEA sentences.
Any suggestion?
Giuseppe
IZ1GCL