Virtual Directory in IIS 5

I am setting up my Windows XP Pro laptop to do some web design work. I set up
the IIS 5 web server. I created some virtual directories so I can store my
files in my document directory instead of wwwroot folder. I did the same thing
on my desktop. I have a wireless network. I share the web folder on my desktop
with my laptop. I can see and change files that directory from my laptop. I
want to set that directory as a virtual directory from my laptop. When I go
through the wizard it does not allow me to select that directory. How can I set
that up.