WPA Supplicant doesn't see my SSIDs?

Now that we've got WPA support I decided to give it a whirl with one of
the WPA-enabled wireless networks I spend time near. I've successfully
brought up a Windows machine on this network, but FreeBSD eludes me. It
seems like the ath driver or wpa_supplicant are not seeing the SSID for
some reason.

/etc/wpa_supplicant.conf:

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=1

network={
        ssid="external"
        scan_ssid=1
        psk="MyPreSharedKey"
}

Output from wpa_supplicant -ddKt -i ath0 -c /etc/wpa_supplicant.conf -Dbsd:

Jun 16 15:02:16.600289: Initializing interface 'ath0' conf 
'/etc/wpa_supplicant.conf' driver 'default'
Jun 16 15:02:16.600422: Configuration file '/etc/wpa_supplicant.conf' ->
'/etc/wpa_supplicant.conf'
Jun 16 15:02:16.600440: Reading configuration file
'/etc/wpa_supplicant.conf'
Jun 16 15:02:16.600483: ctrl_interface='/var/run/wpa_supplicant'
Jun 16 15:02:16.600950: ctrl_interface_group=0
Jun 16 15:02:16.600973: eapol_version=1
Jun 16 15:02:16.600984: ap_scan=1
Jun 16 15:02:16.600992: Line: 6 - start of a new network block
Jun 16 15:02:16.601005: ssid - hexdump_ascii(len=8):
     65 78 74 65 72 6e 61 6c                           external        
Jun 16 15:02:16.601026: scan_ssid=1 (0x1)

...  <PSK lines trimmed> ...

Jun 16 15:02:16.677502: Priority group 0
Jun 16 15:02:16.677512:    id=0 ssid='external'
Jun 16 15:02:16.677523: Initializing interface (2) 'ath0'
Jun 16 15:02:16.677847: Own MAC address: 00:0e:9b:6e:60:fc
Jun 16 15:02:16.677862: wpa_driver_bsd_set_wpa: enabled=1
Jun 16 15:02:16.677875: wpa_driver_bsd_del_key: keyidx=0
Jun 16 15:02:16.677888: wpa_driver_bsd_del_key: keyidx=1
Jun 16 15:02:16.677899: wpa_driver_bsd_del_key: keyidx=2
Jun 16 15:02:16.677910: wpa_driver_bsd_del_key: keyidx=3
Jun 16 15:02:16.677921: wpa_driver_bsd_set_countermeasures: enabled=0
Jun 16 15:02:16.677931: wpa_driver_bsd_set_drop_unencrypted: enabled=1
Jun 16 15:02:16.677947: Setting scan request: 0 sec 100000 usec
Jun 16 15:02:16.778153: Starting AP scan (specific SSID)
Jun 16 15:02:16.778167: Scan SSID - hexdump_ascii(len=8):
     65 78 74 65 72 6e 61 6c                           external        
Jun 16 15:02:24.734030: Received 0 bytes of scan results (4 BSSes)
Jun 16 15:02:24.734051: Scan results: 4
Jun 16 15:02:24.734065: Selecting BSS from priority group 0
Jun 16 15:02:24.734075: 0: 00:0e:83:af:77:f5 ssid='' wpa_ie_len=26 rsn_ie_len=0
Jun 16 15:02:24.734087:    skip - SSID mismatch
Jun 16 15:02:24.734096: 1: 00:0e:38:51:ca:6c ssid='' wpa_ie_len=26 rsn_ie_len=0
Jun 16 15:02:24.734108:    skip - SSID mismatch
Jun 16 15:02:24.734116: 2: 00:0f:66:18:20:00 ssid='SDC-WAP-001' wpa_ie_len=0 
rsn_ie_len=0
Jun 16 15:02:24.734129:    skip - no WPA/RSN IE 
Jun 16 15:02:24.734137: 3: 00:07:eb:30:c6:de ssid='' wpa_ie_len=0 rsn_ie_len=0
Jun 16 15:02:24.734149:    skip - no WPA/RSN IE
Jun 16 15:02:24.734157: No suitable AP found.
Jun 16 15:02:24.734168: Setting scan request: 5 sec 0 usec
^CJun 16 15:02:26.482136: Signal 2 received - terminating
Jun 16 15:02:26.482153: No keys have been configured - skip key clearing
Jun 16 15:02:26.482163: wpa_driver_bsd_set_wpa: enabled=0
Jun 16 15:02:26.482180: wpa_driver_bsd_set_drop_unencrypted: enabled=0
Jun 16 15:02:26.482191: wpa_driver_bsd_set_countermeasures: enabled=0
Jun 16 15:02:26.482202: No keys have been configured - skip key clearing
Jun 16 15:02:26.485314: wpa_driver_bsd_set_wpa: enabled=0

I know from my Windows machine that the MAC addresses for my APs are IDs
0 and 1 in the above output. 2 and 3 are some other networks that also
happen to be in the area. The odd thing is the empty SSID string which
leads to an SSID mismatch. I tried setting my SSID string to an empty
string ("") but still got a mismatch.

Even if I had the PSK wrong or some other encryption setting wrong, I
should still see the SSID, shouldn't I?

Any suggestions?


-Snow