The following is from the WLC 4.2 config guide. It may apply to the WET200.
Note*** The controller supports only Cisco WGB products. Linksys and OEM WGB devices are not supported. Although the Cisco Wireless Unified Solution does not support the Linksys WET54G and WET11B Ethernet Bridges, you can use these devices in a Wireless Unified
Solution configuration if you follow these guidelines:
1. Connect only one device to the WET54G or WET11B.
2. Enable the MAC cloning feature on the WET54G or WET11B to clone the connected
device.
3. Install the latest drivers and firmware on devices connected to the WET54G or WET11B.