Check the German site Navigationsgeräte.
There you can find a thread (MIO v505/735 DVB-T Navi - was alles machbar ist #2) about unlocking Mio505/735. Unfortunately the site lanquage is German, but there is a lot of information.
If you use an unlock program for your device. The TV link will not appear on the menu.
You will have to create a path in unlock setup to access it. It will not run properly due to memory loss.
Just edit your program files/mainshell folder/mainshell.xml & mainshell.ini files using notepad or wordpad.
Just follow the file formats for editing.
Change the GPS software name to what you want to install. Ensure that the path is correct.
Ensure that the " STR " is correctly rename.
Change the icon if you need to. The size same as the 3 listed icon.png.
backup a copy before editing.