I am using Cisco AP352's as AP's on a WISP network. I have customer's buying their own CPE and most talk just find with the 352's. I have one customer that has bought a Smartbridges AirPoint Total. It does not seem to want to associate with the Cisco AP even though it sees it just fine. A note in the unit's user guide states:
"smartBridges use Address-4 field, which is an optional field as specified by IEEE 802.11b standard. All the IEEE 802.11 b compliant wireless access points supporting this field can be used with Client-Bridge mode."