LoanBroker example occasionnally hangs

Often, the loan-broker example hangs.

When that happens, the client (launched with "ant") hangs for a while at [java] Sending request and eventually gets a javax.jms.JMSException: EDU.oswego.cs.dl.util.concurrent.TimeoutException

When that happens, nothing at all is logged on the server (launched with servicemix.xml). Once in that state, it stays like that (until restarted).
If the server is good at first, it often gets into that state at the second request.
Occasionnally, 1 request in 2 succeed (i.e. first succeeds, second hangs, third succeeds, fourth hangs...)