Well it isn't really reflective flooring :P, its a work around of it. But never the less is can be achieved and what's more, the r_speeds can work out ok. Now the basic thing is, you just copy what you have done and flip it over.

(fig 1.0)

As you can see here ive copied the top part and flipped it over, it anit as easy as that though, but just about.

Now what you need to do is select the items you want reflecting, before this though, make your floor 1 tiny unit thick, (in other words make it the thickness of the smallest unit size) Now select it all apart from the floor, everything but the floor. Then copy and paste it.

Now with your objects selected select tools > transform from the toolbar, and make sure rotate is dotted, and in the Y column I put in 180 and clicked ok, however you might have your area in facing another direction, so try out different values, like 90,180,270, etc.

What you now need to do is align it up with the top piece, if you align it with the floor, at the bottom, well it would leave a gap, so go right through the floor when aligning, just imagine the floor anit there, in fact select the floor and hide it, (by clicking the red dotted square in the picture toolbar). Hopefully you know what I mean, i.e. in my picture above (fig1.0) each cylinder on the top part is aligned with the top of the cylinders on the bottom part.

Anyway once your all aligned, what you need to do is select the floor and tie it to a func_wall,(to unhide select the small grey cube from the toolbar near the red one) in the properties change the render mode to texture and the fx_amount is how much it will be see-through, for mine I chose 55. Thats all the properties you need to change. Its now done! so off you go and compile it and see what it looks like.

You might see in my picture ive added a plant, I used the actionhl fgd file for this, you can check out how to put models in actionhl here. What ive just realised it that you can play it in halflife deathmatch, so its plausible that you could make a dm map using the actionhl fgd file to put in models, (as the hl dm fgd file dont allow it, crashes). Anyway what I was going to say is that ive had to flip the models upside down for the plants. To do this in the angle properties of the plant, I have selected an angle of 270, so they pointed downwards.