From previous response from you (Pmease):
"QB relies on Java's process facility (process.destroy()) to terminate a forked process and it does so by sending SIGTERM. If the process won't respond to this signal, the process is not able to be killed.
Sending SIGKILL requires native code on different platforms. Please submit an improvement request at track.pmease.com for this improvement."

This would be the request to make it.
Cheers!