OpenAPI method to generate from a DCR

System

In short, is there an OpenAPI method to generate an output file from a DCR? Or to run an arbitrary TeamSite command as a given user?

We are replacing the workflow instantiator CGI with a JSP which means I can call OpenAPI methods when the job is being created that connect to the filesystem as the user creating the job rather than the SYSTEM user that Workflow ExternalTask processes run as by default on windows (no matter what you set the owner attribute to). So theoretically I could generate the output file(s) when the job is created, which would cause TeamSite to show the last modified user as the user who last modified the content rather than SYSTEM.