Please Help!

I've decided to place Slate Tile over my existing concrete patio.

Grooves have been designed into the patio for a decorative effect as well as to allow for expansion.

Originally, I had planned to fill in the grooved areas with a patching compound to level the surface and lay the tile over as necessary.

I have now read elsewhere that I must respect these "expansion joints" and NOT tile over them and thus integrating them into the design. I would would take a heck of a lot more effort but I suppose I can do this.

However, I still must fill in the space with some sort of material such as grout in order to have a functional patio. I live in San Diego so we are subject to a rather temperate climate.

What is the best method to deal with this situation? Is there more preferred compound to use in these "joints" in lieu of grout?

Ultimately I am not beyond replacing the tiles if they crack.

All The Expansion Joints Are Is For When The Slab Moves It Will Crack Where It Is The Weakest, So The Therory Here Is To Make These Crack Predetermined To Be Small And Run Straight, You Can Run You Tile Just As You Had Planned As For Filling The Joints On The Slab You Can But It Will Still Crack Because Its Designed To, But It Won't Hurt It By You Filling It In, As For The Tile Once You Have It Laid And It Has Dried, Chalk You A Line Where The Expansion Joint Was On The Slab And Cut Down Just Below The Slate, This Way When It Crack It Cracks On The Joint, You Can Either Fill This Tile Joint You Cut In With Grout Or A Exterior Grout Caulk That Will Match Your Grout.

I plan to put slate on a concrete porch. What do I use to stick the tile to the concrete and what do I use to grout the slate peieces?

Please answer my question as stated above!