Concrete has small openings in it left behind from its drying process. Water evaporates in a process called Curing. It leaves behind very small holes called micro-pores. The micro-pores, separated by thin layers of concrete, can be easily broken into with enough force. So, like a sponge with holes, concrete's holes invite water to seek it's own level by entering the voids left from the drying process.

What type of below grade waterproofing are you using?

Check here for the finest information´s

http://www.doerken.de/bvf-en/

Drainage planes (Delta, Platon, etc), are in my opinion a better way to waterproof. Rather than relying only on stoping the water from getting into the wall and basement it does 3 things:

1. It primarily stops water as closed membrane

2. It prevents the build up of hydrostatic pressure directly against the wall

3. Any water that does get through membrane then has a large airspace to drain down and into the drainage pipe.

I had to tackle this same basic issue, but not exactly the same situation. Near the end of this thread I show what I did to shed water over the waterproof membrane. http://www.greenbuildingtalk.com/Forums/tabid/53/view/topic/forumid/4/postid/44303/Default.aspx
Take a look at it near the end to see a problem I had with the ICF foam to membrane transition and how I solved it. This won't work the same in your case but I think you'll be more aware of potential problems.

You might be able to lap the mesh for the stone over the membrane and build a mortar transition from the foam to the membrane. You'll want to fasten the mesh, or lath as the masons call it, for the stone to the ICF blocks with screws. It'll work good. You can take the stone all the way to soil, right?

Not that you asked about it but I'll get a picture in a day or two to show how I transitioned from Hardiplank siding to the stone. The mason who put up the stone was impressed.

Check the following link:

http://www.buildingsciencecorp.com/resources/presentations/Dallas_Zero_Energy_House.pdf

It was for a project the Building Science Corporation worked on that used Durisol ICF, cultured stone and Hardie plank. The pdf is really long, but at the end, there are some really good detail/flashing ideas.