No control over the router? Hmmm… I’d say: install apache, set it up to listen to port 8080 (why not also 80 and 443?) using ssl and use it to proxy the connection to the servoy server using an AJP connector, this way no matter what port the users hit, they are always connecting using ssl. The extra advantage is that it’s easier to set up SSL on apache than on servoy’s tomcat.
More info on my website: http://www.sintpro.com/downloads/Advanced_WebClient_Dev_&_Deployment.pdf