We have been trying to connect a smart bridge with an Atheros radio and Monowall to a Tranzeo TR 6000. When we associate without WEP things go fine, but when we use WEP they will not associate. We did have problems with the Tranzeo and smart bridge associating, but solved this by keeping transmit rate above 1 Mbps.
Because both products support WEP with 64 and 128-bit keys, it seems likely that you are experiencing a WEP key value mismatch. Tranzeo recommendations for debugging WEP problems can be found on their website. Note that Tranzeo requires WEP keys to be entered as hexadecimal values. Mistakes when converting from hex to ASCII are a common source of error. Another common problem is choosing a different WEP key index as your default key -- the key index range, number, and value must match. Finally, make sure that both sides are set to use "open system" authentication (not "shared key" authentication).
You do not describe the mode of operation used by your Tranzeo; I am not sure if you are bridging or using a client/AP configuration. I have heard of products that do not support WEP between bridges; if your WEP keys match and you are bridging, contact vendors to verify support. Finally, try connecting a different client/AP to each device to determine which end is behaving differently than you anticipated when WEP is enabled. Capturing 802.11 management frames can help you spot where the problem occurs.
This was first published in October 2006