Is there anything draining into the stack below your tie in?

 

What I have done in similar cases is to core drill part way through the deck using a bit as big or bigger than the drain body. Then finish drilling through using a 3" bit to receive a 2" drain pipe.
Chip out the core piece, set the drain in the recess and raise/lower the adjustable top grade.
I used a JR Smith 2005- http://www.jrsmith.com/Floor-Drain-with-Adjustable-Strainer-Head
Plastic models are also available.
Anchor in some fashion from the bottom side. Then fill the topside of the flange with a no shrink grout or some product of your choice to floor level.
The only draw back is that the floor will not have a guaranteed water tight seal..... This method is really only for WH pan drains, ect.

 

I was at menards today and saw a floor/shower drain similar to what Eplumber linked to. I picked one up and am going to measure what diameter hole it will need and will probably rent a 5 or 6" core bit and then a 3" core bit to drill the holes and create the "ledge" Eplumber talked about. Looks like the drain flange has some holes for anchors and I can just use some tapcons to secure it to the "ledge" and then pour some non shrinking grout to fill in around the drain.

Eplumber, any tips on chipping away the concrete for the bigger diameter hole? Just a chisel bit in my sds and go at it? So drill the 5 or 6" daimeter hole maybe 2" deep, then drill the 3" diameter hole all the way through, then chip out the concrete from the bigger hole 2 inches deep? Is that the correct procedure?

Thanks for the help.

 

Pretty much- I would chip- at an angle- from the 3" toward the larger hole's edge
Also, what about rebar or cables?