Component video isn't RGB with sync on green. Component video is more like S-video with the chrominance split up even further. The luma on the green and the chroma, Cr and Cb, must get converted to RGB. It's not just a cable modification. The sync is carried on the luma, the green plug, and must be stripped off the luma. The LM1881 will do this for you, but it'll only give you a composite and vertical sync. Horizontal sync will have to be aquired from the composite sync if you want both H and V sync, which most VGA monitors require.
Please post a schematic/diagram/pinout or something. We don't know what pin is what.
But, let me tell you, if you want VGA out of your PS2, you need to run a progressive scan game (no, regular ones will NOT work) as well as have a fairly complex circuit to convert the component video to VGA and do it well without much noise and with the right colors. A component video cable and a sync stripper IC won't do it for you.