To get it to appear in your pokedex, make an egg. Click on the little edd checkbox at the bottom right of the screen, and set the value to 1. The egg will hatch in around 400-500 steps, and viola, u have the pokemon at lvl 1 with its  natural stats (I think) and an entry in ur pokedex. The only problem is that u have to set its basic moves too. Or it hatches with zero moves at all.

Now if someone could tell be how I can hack the three items (oaks letter, azure flute, membership pass) AND be able to use them to cactch those damm event pokemon, I´d be greatly indebted. XD

Cheers!