I can't get my headset (Sony Ericsson HBH-IV835) to work with headsetd.

Installed libsbc/plugz from svn using instructions here: 
http://bluetooth-alsa.sourceforge.net/build.html (I wrote ebuilds to check 
out and compile the two apps so I had a record of the files installed but 
otherwise the process was identical, have attached these just in case).

Rest of my system:
gentoo/amd64 2006.1
bluez 3.9
kernel 2.6.20-gentoo
CSR USB Bluetooth 1.2 dongle

This setup used to work with btsco, but the kernel module for it won't compile 
on 2.6.20.  Devices are definately paired, service discovery is working, etc.

~/.asoundrc:
pcm.headset {
        @args [BDADDR TIMEOUT]
        @args.BDADDR {
            type string
        }
        @args.TIMEOUT {
            type integer
            default 6000
        }
        type        sco
        bdaddr      00:18:13:7e:bc:7a
        timeout     $TIMEOUT
}
ctl.headset {
        type sco
}

Results when trying to play audio through headset

$ mplayer -ao alsa:device=headset $random_video_file
MPlayer 1.0rc1-4.1.1 (C) 2000-2006 MPlayer Team
[...]
alsa-init: playback open error: Connection timed out
Could not open/initialize audio device -> no sound.
Audio: no sound
Starting playback...
(video plays at this point, with no audio)

$ headsetd -n
headsetd[3540]: Bluetooth headset daemon version 0.5
	headsetd[3540]: Configuration phase ended: target bdaddr is 
00:18:13:7E:BC:7A, timeout is 6000 ms
headsetd[3540]: Changing state: Idle-->Paging
headsetd[3540]: Changing state: Paging-->Connecting
headsetd[3540]: Changing state: Connecting-->Ready
headsetd[3540]: Changing state: Ready-->Opening
headsetd[3540]: unable to open SCO channel to headset: Connection timed out
headsetd[3540]: Changing state: Opening-->ZombieAppl
headsetd[3540]: Appli closed socket
headsetd[3540]: Changing state: ZombieAppl-->Idle


I have reset my headset, deleted the contents of /var/lib/bluetooth on the pc, 
re-paired continuosly, but get the same result each time.

What have I overlooked?