Lynn, The deck is to shallow to mulch. I bought the 42" mulching deck for the Walker and was dissapointed at first.
I ended up buying Gator Blades for the mulching deck, and I use it all summer long. However with my picky customers I go over the lawn twice. The 2nd time I crisscross the lawn and make my stripes a tad wider and just fly over it and hide the clippins. Still beats emptying the bagger, anyday.
If the lawns are to wet I switch back to the bagging deck.
The only other option would be to buy a big side discharge and use the gator blades. This is a must on 1 acre plus properties.