Blender Retopo not working for me

I know this has been discussed in previous threads, because I read several.
However, I feel that either the explanations offered or my attempts are leaving something out.
I have a hand model that combines both extruded modeling for the palm and fingers and a thumb that was done in sculptmode. The thumb is totally out of proportion, but that is not the issue here. I am still learning the program.
I thought that I could reduce the poly count using retopo.
When I follow the instructions and draw with the pen in top view and then apply, the added stuff is projected and transformed to the plane on which the object data origin is located. In other words, it is sent to the interior of the hand which is centered on the grid. Is there some setting that will limit the projection to the surface of the model? I have the depth buffer on, so that seems not to be the answer.
Is it that “xray” setting that was mentioned as optional? Where is that? Did they mean wireframe?
I have reviewed the very informative tutorial and the other info in the wiki.
I would appreciate some advice.
Thanks, mitcorb

Hm… I haven’t messed around a ton with the retopo tool myself but the thing I use to get it looking right is just to start with a plane and extrude out from that. One thing that might help that you probably know is that the plane and the object you are retopoing must be different meshes. That one got me for a while.

And the Xray button is in the object panel which is hotkey F7 under the draw box. It really helps cause the object you are retopoing hides a ton of the plane you are working with.

I don’t use the draw feature much. The best way is to add a plane and put it in front of the ‘form’ mesh, go into edit mode with the plane, delete three vetices, extrude out a few edges, and hit retopo, select all the new vertices, and move them a hair to get them to adhere to the surface below them, then a to deselect all, right click to select a vertex, and just keep extruding and facing. you know the buttons that switch between vertex, edge, and face select mode? there’s another button that looks like a cube, that if clicked, makes your mesh semi transparent while in solid draw mode. be sure to click that so you can see your vertices as you build your new mesh.
(edit) basically, what dudebot said, heheh

In my case, and I dont know if this has to do with my cheap onboard graphics card, until I pressed Xray button the new retopo-ed mesh where not exactly over the original mesh. Pressing the button fixed the damn thing and now retopo works and adapts exactly and perfectly over the old mesh.

It works equal for objects, objects with x-ray button on, wil be drawn first in the Z buffer.