Hi Uomo,
Not sure how feasible this would be, since Send to Folders are part of the same process as all other actions, and will use that process's credentials. This would require implementing support for allowing multiple users to use the services at once, something which is a lot of work(if even possible) for relatively little benefits. So I don't think this will be implemented.
Workaround: try maybe using the "External Program" action to execute a third-party program, script or .bat file that will do actions under different credentials, if you have the proper tools to do something like that. You may have to do a bit more research on that subject, however, as I haven't done it myself, just suggesting a possible workaround.
Regards,
Raphaël Lalonde Lefebvre