ExternalTasks touching file set modified to SYSTEM

System

On Windows 2000, no matter what I set the owner attribute of an externaltask (or CGITask) is set to, if the process touches a file in TeamSite (through iwpt_compile.ipl for instance, or even iwextattr), TeamSite shows the file as last modified by the user SYSTEM. This is inaccurate and useless information (all files that are workflowed show SYSTEM as last modified). Is there any way to fix this, for instance to set the last modified user explicitly?