We recently purchased two 3CR17572-91 - Switch 4500 PWR 50-Port and some HP X120 1G SFP LC LX (Part# JD119B) transceivers to use with these. I can't get them to work. Even when they are connected back to back using just a Fibre patch cable nothing happens. I'm suspicious these transceivers are not compatible with the switch. Can anyone confirm my suspicions or suggest what i might be doing wrong.