It is likely that a WS using WS-BA will use a JTA transaction in the service, Compensate and Close methods. The problem is that failure windows exist in this scenario. For example, when a JTA transaction is committed in the service method, a failure before confirmCompleted(true) is invoked will result in this commit not being compensated.
There may be other windows in Compensate and Close. This needs investigating.
The WS-BA to JTA bridge would ensure that the transaction is not committed until confirmCompleted(true) is invoked. It should do something similar for Compensate and Close.
This would need extensive testing, including crash recovery. The WS-AT JTA bridge (TXBridge) can be used as an example, as I believe it will have a lot in common.