You may be right :D
Just one question then. I've tried with fedora and with fedora 18 it founds
the Serial device on system-config-printer, but it is not the case with
trisquel 6.0 (I've not tested with Ubuntu 12.04).
I'm even capable of printing using a different driver using cups on Fedora,
but nothing to do with Trisquel it just says : "Unable to open serial port:
Permission denied" when using "serial:/dev/ttyUSB0" ... This made me remember
Parabola (Arch Linux).. don't know why..
Do you (or anyone else) know how to solve this ?