I have bought a Samsung 48" television.  The remote control works OK, except that I can't find the button to jump to the previous channel. To put another way, return to previous channel. On my remote there is a "Return" button with a circular arrow, but that only works on menus. There is no "Pre-ch" button on this remote. I have also tried pressing "0" as suggested elsewhere but that doesn't work.  Which button is the one to return to the previous channel? It is a very important feature and I can't believe that Samsung would not design it for my TV.

The TV model is HG48ED690DB and the remote is  AA59-00818A.