Can You Domain Map with Sub Directories?

I am trying to domain map with my multisite Wordpress intall.

I have it set to create new sites using sub directories instead of sub domains.

For example, I want to use http://www.romae.org/romeinsitu as the target for my domain mapping URL which would be romeinsitu.com.

When I pinged my site and entered the IP address, the domain mapping works but it takes the URL to a redirect page with no content.

It gets more complicated. You might want to have a seat for this! I am hosting multiple domains on one host, (romae.org, marlinsnation.com, phrenes.com, etc.) so I guess this means that these domains, although they are hosted, are sharing the same IP address.

So...any suggestions? Thanks!