Wireless and VLANs - VLAN mapping causes authentication failure

When I add a vlan mapping for a working SSID authentication then fails.
I've followed the notes in books and on Cisco's web site and cannot see
what is wrong with my config. Could it be that the client software
needs to recognise 802.1q wireless frames?

I have the essential config listed below along with the one statement
that is causing the problem - adding a vlan mapping to an otherwise
working SSID - in this case SSID test and vlan 15. Can anyone give me a
clue as to what is stopping this working??? The client uses LEAP if
that's any clue. TIA.

!
bridge irb
!
interface Dot11Radio0
!
encryption mode ciphers ckip
!
encryption vlan 15 key 1 size 128bit 7 <key1> transmit-key
encryption vlan 15 mode wep mandatory
!
encryption vlan 26 key 1 size 128bit 7 <key2> transmit-key
encryption vlan 26 mode wep mandatory
!
ssid primary-guest
vlan 26
authentication open eap eap_methods
authentication network-eap eap_methods
accounting acct_methods
guest-mode
!
ssid test

vlan 15 <-- adding this causes authentication to fail

authentication open eap eap_methods
authentication network-eap eap_methods
accounting acct_methods
!
speed basic-1.0 6.0 9.0 basic-11.0 12.0 18.0 24.0 36.0 48.0 54.0
rts threshold 2312
station-role root fallback shutdown
bridge-group 1
bridge-group 1 subscriber-loop-control
bridge-group 1 block-unknown-source
no bridge-group 1 source-learning
no bridge-group 1 unicast-flooding
bridge-group 1 spanning-disabled
!
interface FastEthernet0
no ip address
!
interface FastEthernet0.15
encapsulation dot1Q 15 native
no ip route-cache
bridge-group 1
no bridge-group 1 source-learning
bridge-group 1 spanning-disabled
!
interface BVI1
ip address 10.46.137.169 255.255.255.224
!
ip default-gateway 10.46.137.161

> clue as to what is stopping this working??? The client uses LEAP if
> that's any clue. TIA.

Well it's not an answer to the question but that's not a great
authentication method. Even Cisco admit that you'd be better off not
using it.

http://asleap.sourceforge.net/

http://www.cisco.com/en/US/products/..._bulletin09186
a00801cc901.html

http://www.lanarchitect.net/Articles/Wireless/LEAP/

http://searchnetworking.techtarget.c.../0,289142,sid7
_gci959510,00.html

Strong password policies and numpty users just don't mix.

David.