You need one rated for wet locations if it's inside a shower. The enclosed ones frequently are. I'm not sure how "vertical" your skylight wall is, but HALO does make some fixtures that are designed to tilt more than your average eyeball light (they make these so that you can use them in an up to 6-in-12 ceiling and have them still point straight down).

The wall I wish to mount the light is 90' vertical, so the light housing would be parallel with the ceiling of the bathroom. The light would then hopefully reflect around and light up the tub area. Good idea on the wet location housing, thanks.

nelo-
your post is confusing-
What do you mean by 90' ? did you mean 90 degrees?
If it is 90 degrees it would be perpendicular to the ceiling, not parallel-
Are you saying that the recessed light will be mounted on a wall?
Please clarify for us!
Thanks

The light HOUSING will be parallel to the ceiling. Its FACE will be perpendicular.

He wants to install the light in a WALL, like, a vertical plane, 90° to the ceiling.

I am sorry I was confusing. my skylight tube walls are pependicular to the ceiling of the bathroom. I would like to mount a recessed type light in the wall of the skylight, the light housing would be parallel to the bathroom ceiling. Normaly a recessed light housing would be vertical not horizontal. I dont know if this is a safe way mount the housing. thanks Nelo