How do I play PS2 games online on PS3?

Games that are online compatible that I own(a few): MK Armaggeddon, NCAA 07, Madden Series, Ratchet & Clank UYA, SVR Series and SWB2. I don't get it for Star Wars it works, but WWE it doesn't! It needs an ethernet cable but for SWB2 it satisfies??? Please help, desperate to find out the faulty and leave precarious tips to help me. Thanks.