Problem Hitting non-inetpub\wwroot virtual directory

[muzzy]

hi all. my problem:

obtained an exisiting vs.net solution from our source safe. solution
contains an asp.net project ("Site"). i would like the project to
reference a virtual directory that DOES NOT map to the default
c:\Inetpub\wwwroot directory - instead, i would like to map it to my
local source safe directory ("c:\projects\Site").

*create vd ("Site") in IIS (localhost\Site), maps to c:\projects\Site.
*open vs solution from c:\projects\Site
*vs.net prompts me to select the location for working copy of the web
project
*attempt to assign localhost\Site as working copy location
*click "ok"
*receive error:
"One or more of the project's destination paths are invalid. To
open this solution, you must specify valid paths for each project. The
error returned was "The Web at 'http://localhost/Site/' already
contains a project. You need to choose another location for your Web
project."

any insight would be greatly appreciated. in various groups, i have
found this problem posted several times - but no answers.

thanks,
dave