Adding a light to a 3 way switch

[jean]

In my stairway, there is a light at the top that is controlled by a switch at both the top and bottom of the stairs. I have added a recessed light at the bottom of the stairs.

But I can't figure out how to wire it in. I would like it to be controlled with the light at the top of the stairs, but I have no access inside the walls to get a wire through to the top light.

The only wire that runs to the bottom switch is three wires, connected to a three way switch.

How can I wire in this new light without being able to get to the upper switch or the upper light?

Thanks in advance for any suggestions! This one has me stumped!

[irregularjoe]

why don't you have access to the walls?
Is there an attic?
You need to tap into either the top swich or the light. The 3 wire bottom switch is not a full circuit.

Did you ever see OHM'S mother in LAW?...... SHOCKING!

[jean]

The walls of the stairway are finished, and the stairs go down to a finished basement. The basement was finished using sheetrock, and provides no access to the area.

Is there usually some way to get through a level of a house? Maybe I could run a some romex beside a pipe that goes through all floors? Haven't found one yet that would work.