Won't Connect To Preferred Networks Using Wi-Fi Policy

Hi,

I've been setting up and configuring our new wireless access point (3com
OfficeConnect). As we have newer wi-fi cards and some older wi-fi cards we
need to use both AES & TKIP. I have managed to get it working with WPA/TKIP
& WPA2/AES. As Wi-Fi Group Policy only let you specify TKIP _OR_ AES not
both, the AP lets you define multiple SSIDs and security policies, so I have
SID001 with WPA2 and AES and SID002 with WPA and TKIP.

Configuring a laptop manually I can connect to both SSIDs using both types
of security. However as we have so many laptops, I have configured a
wireless group policy. In here I have 1 policy called Company Wi-Fi, with
the preferred networks, 1st is SID001 - WPA2/AES, 2nd is SID002 - WPA/TKIP.
This way, the clients should try the 1st preferred network, then if they
don't support AES fall back to TKIP. Now here comes the strange bit, if I
uncheck 'Automatically connect to non-preferred networks' (as we don't want
users laptops connecting to unauthorised networks with out their knowledge),
apply the policy to a laptop, reboot, the laptop will NOT connect to either
of the networks defined in the group policy, however if I check
'Automatically connect to non-preferred networks' apply the policy, reboot,
and try again, the laptop will pick up SID001 and connect without problem.

Why is this happening? unchecking 'Automatically connect to non-preferred
networks' should stop it from connecting to preferred networks should it?

Any help would be greatly appreciated!

Ben