dens-guard what to do?

I am currently installing a 4x5 ceramic tile shower. I am planning on using G. P.'s dens-guard backer for the walls and ceiling. If I tape and waterproof the joints, would you still need to apply a waterproof membrane to the walls, or lay directly on the backer itself?

From the GP website:

(Keep in mind this product is not a waterproof product.)

Walls
Step 1 Position 1⁄2 in. DensGuard panel next to framing
With blue side away from studs, fit ends closely. Cut panel
To required size and make cutouts. Leave 1⁄8 in. gap
Between tub deck or shower pan and DensGuard edge.
Do not use vapor barrier behind DensGuard Tile Backer,
DensGuard has a built-in moisture barrier on the face.
Step 2 Framing should be spaced no greater than 16 in.
On center without blocking and 24 in. On center with blocking.
Space fasteners 6 in. On center along studs. Drive fasteners
Flush with coated surface, do not counter sink.
Step 3 Embed 2 in. Glass fiber mesh tape in a skim coat
Of the tile adhesive on all joints and corners. Caulk plumbing
Penetrations and abutments to dissimilar materials (I. E tub
Deck) with flexible sealant.
Step 4 Set tile. After planning the layout of the tile
And marking the area with chalk line, spread adhesive
With notched trowel following the adhesive manufacturer’s
Instructions. Push, twist and press tile into adhesive to
Ensure adequate coverage.
Allow minimum of 24 hours curing time before grouting.
Step 5 Apply grout as directed by grout manufacturer for
Tile type and spacing.

Berry,

Since it's large shower I presume you'll have a standard method pre-slope-membrane-mud deck with tile on the floor in that order. How will you treat the deck/Densguard intersection? You shouldn't bury the panels, but they need to be held in place somehow. Have you studied their silly sketch on how they think you should do it?

What's your plan?

Jaz