<< Now the customer wants a secured connection to the web server
you don't have a domain, but you can still generate a certificate for the server. (just set the domain name to the server name, like DAISY or whatever it is. No periods in the domain name.)
The connection will be secure, but "untrusted". So the first time the tablet goes there they'll get a warning and need to add an exception to the browser. But then the connection is still secure after that (although more subject to man-in-the-middle attacks.)
cheers
Bruce