Gumstix - Missing Bluetooth Serial Port

I've been rebooting my Gumstix quite a lot and sometimes removing the Bluetooth pairing from my Mac.  When I try to pair the Mac and Gumstix again, quite often the serial port does not show up.  The only way I have found to get around this is to reboot and try pairing as soon as it is booted, if I leave it for a while I don't see the serial port.  Simply restarting the bluetooth software using:

/etc/init.d/bluetooth restart

does not work.  I am investigating ...