My JVC PIP Won't work, pls help!

Hi, I just bought a JVC Flat Screen AV-21ST27. I hooked up all the cables properly: Cable Tv, DVD, VCR are all working and viewable. The reason I bought this model was because of the Picture In Picture (PIP) feature, the problem is, when I turn on the PIP and click the channel changer for the PIP on the remote, both the main picture and subpicture change. So, both the main picture and subpicture are always on the same channel. When I use the channel changer for the main picture, both pictures also change.  However, when I switch the PIP to Video 1 and swap the main picture with the subpicture, the channel changer for the subpicture works. THE PIP CHANNEL CHANGER ON THE REMOTE ONLY WORKS WHEN THE MAIN PICTURE IS ON VIDEO 1 MODE. Please help! Is this a factory defect? Do I have to return the TV? Or did I do something wrong?

Samantha Tan
nomadsportsclub@yahoo.com