PIP on Samsung LE27T51B for PC only???

I have recently purchased a Samsung LE27T51B and so far have only one gripe:
The picture in picture mode is limited to use with a pc.
In the settings menu the pip option is greyed out so it's not possible to alter the source from PC.
Is there any way of getting around this?
One site i looked at suggested that as long as my tv supports (Y/Pb/Pr) i could use an adaptor cable to convert the VGA port into RGB giving me the option of attaching it to my PS2.
It was all meant to be so simple!!
Any advice gratefully received!