Port devel/arduino serial port problems

[Arthur Chance]

I'm trying to get devel/arduino working. Plugging in the USB cable to 
the Arduino creates /dev/cuaU0* and /dev/ttyU0* and I'm manually 
changing them to mode 666 while trying to get started so should be able 
to access them as my normal user. However, the Tools => Serial Port menu 
item in the Arduino IDE is always greyed out, and whatever I set 
serial.port to in ~/.arduino/preferences.txt when trying to upload a 
sketch I always get the error message

Serial port '<whatever serial.port is set to>' not found.

Any hints and clues would be very welcome.

My system is 9.1-RELEASE-p1 and amd64

pkg info arduino shows

arduino-1.0.3_1,1              Open-source electronics prototyping platform

My /dev with the Arduino plugged in and a chmod a+rw done suitably:

fileserver# ls -l /dev/{cua,tty}U*
crw-rw-rw-  1 uucp  operator    0, 242 Mar 13 21:24 /dev/cuaU0
crw-rw-rw-  1 uucp  operator    0, 243 Mar 13 21:24 /dev/cuaU0.init
crw-rw-rw-  1 uucp  operator    0, 244 Mar 13 21:24 /dev/cuaU0.lock
crw-rw-rw-  1 root  wheel       0, 239 Mar 13 21:24 /dev/ttyU0
crw-rw-rw-  1 root  wheel       0, 240 Mar 13 21:24 /dev/ttyU0.init
crw-rw-rw-  1 root  wheel       0, 241 Mar 13 21:24 /dev/ttyU0.lock