ZBrushCentral

Retopo on to a base mesh...

Hi, I need help rotopologizing in zbrush. I know how to do it vertex by vertex but I already have a low poly mesh I would like to use. I tried to project it on the whole low poly mesh but I lose all of the small details. When i do it vertex by vertex then use projection, all the details do appear. Is there anyway for me to do this without have to remake the whole mesh? Thanks in advanced.