Bill,
For us AppTunnel handles directing all traffic from the app directly to the MI century servers. So the app can directly reference the BOE web servers address. In your case, its a 2 step process. You will have to point your app at the MI server URL and then have MI redirect the traffic to the BOE web servers. If you're not familiar with it, it called a reverse proxy. You'll also want to make sure that there is some sort of authentication from the app to the MI century. We evaluated this, but it was much simpler and user friendly to let AppTunnel provide that functionality.