As you can see few threads down I asked the same thing about panasonic hu. I search the web for few days and found a solution. You need a VGA TO CGA/CVBS/S-VIDEO CONVERTER.
Thats to convert your video signal from pc to signal that your HU can read over that RGB cable. But, those HU displays work on 480x234 at 15Hz as I've found out, and I dont know how your PC video would look like on a screen like that.
And if you want the touch function to work on your PC, you will need to buy touch screen usb controler and wire it on your HU. Only thing is that you should put a relay on it so you can choose if you want tu use touch to controle HU or PC.
All that should work as I found on some old thread on some forum, where a guy used all of this to connect on his stock car HU that had same resolution and that RGB input as this HUs.
I've ordered my Converter, but still waiting for it to arrive. I will maybe try it out just to see how it works. But I also ordered new 7" LCD with touch screen and will try to fit it in my 1DIN mechanism because my HU software looks horrible as its out of date from 2006, so I will just use Centrafuse from a PC to control everything. And I will try to connect HU to this new screen just to use it to connect speakers through it.