It's not your device that chooses between mobile and desktop, it's the server that does. Unless there's a way to change it manually (like a full version link) there's not much you can do.
The only way to bypass it in that situation is to have your device pretend to be something else when contacting the server (say desktop Firefox). However, the native PB browser (like most browsers) doesn't have that feature. I believe some browser apps in App World do though.
