Installing an Extend-A-Stay Propane

your set up should be a standard horizontal rv lp tank with a remote fill and bleeder valve. there should be no problem filling it like any other rv mounted tank. the reason they do not want to install the extend-a-stay is it is a temporary connection that has to be disconnected and capped off when ever you move and that's not easy when you have to crawl under the rig its more a safety consideration than any thing else. they want no liability with your setup.