You can... but you have to modify the RXTX source code. I did have /dev/boarduino and /dev/arduino (former was for my FTDI 232 cable plugged into a boarduino and the latter for the duemilanove). You need to look at RXTXCommDriver.java starting from line 519 for version 2.1.9.
I had this working with arduino ver 0014 iirc and java sdk 32bit . I then scrapped that as I wanted to get arduino/java/rxtx working completely with x86_64 and I couldn't compile rxtx.
HTH