Unless your 3COM device is operating as a client (to the LWAPP), I'd be surprised that it worked at all.
Wireless bridging is not standardized so it's pretty rare (if at all) that a bridge from one vendor would work with a bridge from another. They all use their own variations of a base protocol (like 802.11a/b/g), but accommodations are made for timing delay and other conditions found in a bridged environment that wouldn't normally exist in a AP/Client session.
Since they are all doing it their own way, it's unusual that one guy's stuff can work with another guy's stuff.
Any additional details you can offer would help ...
Good Luck
Scott