In current versions of BIS, log files are only written if this feature is enabled.
Under IIS, the BIS_LOG system environment variable controls this behavior:
BIS_LOG=[ OFF | ON | <directory> ]
Valid values include:
The directory must be an absolute path or network path. If the specified directory does not exist, BIS attempts to create it. Note that the containing directory must exist.
The BIS_LOG variable is only examined when the BIS application pool is started or recycled. Be sure to restart IIS after changing this variable so it takes effect.