Drain in slab issues

Hey Everyone,

I have been lurking here for a while and finally have a reason to post.
I am embarking on a bathroom building mission in my basement. The basement was roughed in for a bathroom when the house was built so I am trying to stick with what is there and am determined to not bust up any concrete. I am in a bind with the shower drain however. The drain seems to be cast iron all the way to the trap and from there up is the problem. The trap has a 2" diameter piece of ABS coming out of it through a rubber fitting and then immediatley has a 1 1/2" pvc reducer glued to that "previous owner did it I swear". I would like to get rid of that 1 1/2 piece and be 2" out of the floor so that I can use a Kerdi shower drain. There is only about 1/2" between the bottom of the pvc reducer and the top of the rubber ring in the trap so cutting it off and using a coupler is out of the question I think. I am far from a plumber so if these questions sound rediculous sorry. Is it possible to remove that rubber fitting and replace it with a new one and rebuild from there? How about removing the trap from the line it connects to "via rubber fitting" and replacing the whole trap unit? Is it possible to cut off the pvc reducer and somehow attach more abs to the 1/2 or so to work with? Am I screwed? The following link has pictures of my setup in case what I have said doesn't make sense. http://www.ewehr.com/drain Thanks in advance...

What I see is a fitting that will accept a 2" riser.............But I'm here and you are there. I'm sure you measured it?

A picture would help diagnose the situation.

You may end up breaking some concrete to replace the cast iron trap with a pvc with the desired riser.

I measured. This picture shows it a little better I think. The pipe comming out the top is 1 1/2", it is not glued, just showing the orientation of the fitting.
-Jim, there are some pictures located Here: http://www.ewehr.com/drain

There's got to be a fitting to give you the 2". But, you might consider snapping the trap off beyond the hub that it is connected to, and just replace with pvc. What does the trap look like from close up? You wouldn't want it to fail after putting a new shower in down the road.

New situation

Ok, so after some exploring with the drain I noticed that the trap had a bit of play between it and the rubber fitting. I pulled it out of the rubber fitting with surprising ease. The rubber fitting itself came right out as well. Is this normal? Should those parts come right out with virtually no force? I assumed that they would be glued together but then again I know nothing at this point. This was all done when the house was built about 12 years ago and just sitting in dirt, rock, and a bit of ground water when it rains hard. I am assuming (praying) that I can just go get a new rubber fitting and pop it in and then a new trap from there. Is a cast iron trap better or should I switch it out with PVC? Can PVC just be pushed into that fitting as the old trap was or does it need to be glued as the old abs pipe was in the top of the trap? This will all be burried under concrete when I get it finished so I need to take that into account.