Using the steel frame as a template, I traced a line to use as a guide for drilling through the side wall.  I used a 3/8" carbide masonry bit to drill through the wall, and stopped when the bit hit the exterior tiles. 

The temperature outside was about 25 degrees F, so it was pretty brisk.  I wore eye protection, a dust mask, and gloves through the drilling process.  The drilling was pretty easy, but a bit tedious making all the holes close together.  As you can see, I wasn't about to stand bent over during the drilling, so I made myself comfortable.  

After all the holes were drilled, I rocked the drill in each hole, effectively carving out a channel around the remaining wall section.

Because of the way my cooker is placed on my deck, I determined that I wanted the control valve to be placed behind and on the left side as you face the cooker.  This way I don't need to get behind the K to adjust the flow.  If you are looking down at the cooker, with the lid hinge in the 12 o'clock position, the new opening is in roughly the 10 o'clock position.

The installation instructions call for drilling through the tiles, but because I own a reciprocating saw, I chose to use a carbide blade to slice through the tile.  

I covered the tile with masking tape, then drilled a couple of pilot holes at the corners from the inside.  This let me know where to saw.  Once I got through a section of tile using a careful plunge cut, I was able to insert the blade and cut out the remaining tiles. 

The only real reason for doing it this way, as opposed to tapping out the tiles from the inside is that this way I didn't have to replace any of the tiles at all (Kamado supplies some extra full and half tiles and grout in their retrofit kit)

A 1.5" steel frame gets cemented into the new opening.  Any tile and grout work should also be done before installing the burner.  The manifold will rest on the inside of this frame.

The burner gets slipped through the opening, from the inside of the cooker.  Two flanges (plates) are bolted together (one inside and one outside the cooker) to keep the burner in place (though it can be moved a little bit in the firebox).

A steel rod is fastened to the underside of the burner with a screw to support the cast iron burner assembly.  The rod straddles the firebox.

To finishing the interior assembly, add the  burner cover / charcoal basket.  It is manufactured with a round post on the underside that slips into the center hole of the burner.  

Filling out the inside of my K involves some accessories I've been using frequently.

The top of the accessory "bottom bracket" is about two inches above the cover plate.  This bracket is used to support an 18" grill, or a drip pan, or a pizza stone/heat deflector.

I prefer to use a piece of expanded metal over the air holes in the firebox.

The 10" disk is cut from 1/2" 13 gauge expanded metal sheets available from my local hardware store.  I can cut three disks from the 16x30" sheet in a few minutes using an electric jig saw with a metal cutting blade.

Using the expanded metal grate, in my opinion, makes for easier temperature control, as the round air holes in the firebox are never blocked.  Also, only the finest ash particles find their way to the lower ash pit.  It seems that a disk lasts about 6 months for me before it needs to be replaced.  The newer firebox design lets small pieces fall through the firebox easier, but I still prefer using the grate.

This photo shows the control unit placement with the spring prop in the open position.  I may replace both nuts on the bolts with wing nuts, in case I want to remove the burner quickly for some cooking.  I'm not sure if I'll be doing this, but if I find it useful to take out the burner, I want to make it as trivial as possible.  The Kamado company is also considering making a plug and cover plates to restore the side wall to a solid configuration.

This photo shows the control unit placement with the spring prop in the closed position, with the gas hose attached.

Here some coals are being heated on the coal basket.  The flames lick up the side of the plate and seem to light the coals positioned along the edge of the basket pretty easily.

Another view of the entire assembly while heating some coals.

When the coals are lit, I brushed them off the plate onto the waiting coals in the firebox.  The cutout in the ring makes it easy to clear the top plate.

In April, I got a package from Kamado that included a new flange that is form fitted to the manifolds on the underside of the gas burner.  This goes a long way to cutting down on air infiltration through the frame, making temperatures easier to control.

I have also filled the frame with some "stove tape"... further reducing air infiltration.  The original mounting flange overlaps the new lower flange.

This photo shows the two flanges together, as seen through the opening in the optional mushikamado grill (with center grill insert removed)