thanks for posting here Don -
so, the thing is that you may want to run _multiple_ "Multi-Host" servers on the same machine. I had this situation on one server where I'm running a bunch of sites on port 80 (ie normal HTTP) but also multiple "sub-domains", with a wildcard certificate, on SSL (all on the same machine.)
Now since the program is a service, a number of the service settings need to be unique (like the service name, description and so on). If I hard-code this in the SelfService settings, (as one usually does) then you can only run one. The solution is to make the SelfService settings "variable".
So to make the program run as a service, you first need to set the Service name and Service description to something (unique).
Run the exe, go to the settings tab, enter something there, and click on "save".
(tip: the name can't contain spaces).
Then after that you can run the Exe /is and the service should install.
cheers
Bruce