We are using Nortel Access Points with IAS. Without the correct certificate, it wouldn't even associate with an AP and you didn't get any logs on the IAS.

Because we don't broadcast our SSID, I have configured it the WLAN configuration on the BES.

Config is as follows

WLAN Link Security EAP-PEAP
WLAN SSID ****WLANNet
WLAN User Name bbwlanuser@*****
WLAN User Password ********
WLAN DHCP Configuration True
WLAN Inner Authentication Mode EAP-MSCHAPV2

The * is to blank at corporate names. All we then had to do was sync the certificates (Intermediate and Root because we use our own Certificate Authority)

Then set the profile to use the intermediate and that's all. If this doesn't work for you, I'd check the APs and Radius settings.