Normally the best way from the Lido to VCE (other than a water taxi) would be the Alilaguna Red or Blue lines. I think there was a reason the OP didn't want to do that.

(I saw some kind of model in the terminal at VCE suggesting that they're finally going to move the water dock a lot closer to the terminal -- not quite sure how they're going to achieve that, but it clearly would be welcome! ETA: Oh dear. I just found the project description on the airport's website. All they're doing is putting pretty architect-designed canopies on the dock. They're not actually digging out a channel to move it closer to the terminal. Sigh. Didn't they think of this when they opened the terminal in 2002?)