Setting javaws trace file on linux

[SSH]

I'm testing multiple simultaneous javaws apps running simultaneously
(launched by a perl script) as part of a stress test, and I'd like to
be able to choose where each console log/trace goes rather than them
ending up in :~/.java/deployment/log/javawsRANDOMNUMBER.log/trace

javaws -J-Ddeployment.javaws.traceFileName=test.javalog http://MYURL

should work, but doesn't. Neither does
deployment.javapi.trace.filename nor any substitutions of log for
trace. I'm using Java(TM) Web Start 1.6.0_07. Anyone got any ideas?
Trace/log were turned on the the control panel.