if that preference doesn't work for you, there is nothing else. check if you can open the file while XSI is running using file sharing flags (something like SHARE_READ), and not just the default sharing flags (which is "deny everyone else")
the only recourse you have IMHO is to work write your own logging system, which means an EndCommand event to log commands and also sending the output of your tools to your own file rather than stdout or silogmessage.
