Need help with Picture and Picture

I bought a new tv today, half of the reason was for high definition gaming, the other half was for picture and picture. Now that I've set it up though my tv won't let me have an input via the component cable on a split screen with the component cable set to HD. If I switch the cable back to standard tv it works fine.

I don't want to have the cable at Standard Definition all the time but I don't want to have to change the input type everytime I want to play a game using PAP. I have a feeling it's a problem with the tv(panasonic px600) and I was hoping someone else might have a solution to it. I'm not going to get the elite so using a hdmi is out.

Thanks.