wpa_supplicant problem with Prism card

[David Goodenough]

I have a need to be able to connect to a number of different APs, so I 
thought using wpa_supplicant and its wpa_roam function.  But I am 
obviously doing something wrong.

In order to keep things simple I have turned off security on the AP
I am trying to connect to.

I have a /etc/wpa_supplicant.conf which has the following entries:-

<<<<<<<<<<<<<
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0

eapol_version=1
ap_scan=1
fast_reauth=1

network={
        ssid="21highst"
        key_mgmt=NONE
        id_str="21highst"
}
<<<<<<<<<<<<<

My /etc/network/interfaces (yes I am a Debian sid user) reads:-

<<<<<<<<<<<
auto wlan0
iface wlan0 inet manual
        wpa-roam /etc/wpa_supplicant.conf

iface 21highst inet dhcp
<<<<<<<<<<<

and it never manages to associate with the AP.

However if my /etc/network/interfaces file reads:-

<<<<<<<<<<<
auto wlan0
iface wlan0 inet dhcp
	wireless-essid 21highst
	wireless-mode Managed
<<<<<<<<<<<

it works a treat.

I assume (maybe wrongly) that it takes the ssid from the one it has
selected (and iwconfig supports this), and the mode (managed in this
case) from the fact that it is an AP it is associating with (not an
ad-hoc) and again iwconfig looks good.  iwconfig also reports adequate
signal and the right channel.

I tried using --verbose on the ifup command, but that did not tell me
anything useful.  Can I tell wpa_supplicant to be a bit more chatty and
tell me what is going on?

Any ideas?

David