This answer explains why you can not configure IIS while at the same time as using Ensim.
This article applies to Windows Dedicated Server accounts.
This should not be configured as everything is taken care of from the Ensim control panel. Any work done on IIS may cause conflict and resulting in rebuild of the windows server (unfortunately there is no way of uninstalling Ensim). IIS would overwrite ensim config files and would then no longer synchronise between the control panel and the IIS server.