On the machine where you just have IIS you need install the X-Port component only. Start the setup.exe of Tamino, select custom installation, server components, X-Port component.
Once this is installed you need to modify the registry so the modiis.dll filter knows where to send the request to. This is documented within the documentation, see <tamino_version_dir>/HELP/INSTALL/IWCONFIG.HTM#msiis
#webMethods#API-Management#Tamino