Clarification on subdomains

I know this has been asked before, but I'm looking for a clarification because all the previous discussion didn't spell it out and I don't want to find I had the wrong expectations when I sign up for an addon. Ok, the questions:

To clarify, the "unlimited sub-domains" addon does allow you to have subdomain.mydomain.com that points at a a subdirectory of the primary www.mydomain.com site? Previous comments have said it can point to a "document root" but that is not a clear term for me. Can it point to a subdirectory or somewhere other than the same place as the primary domain. Can that subdirectory be an IIS ASP.NET Application?

The other question I have is, is there a user interface for adding and removing subdomains if I choose the addon? Will I have to go through tech support to make changes? Either way is ok (doing it myself is prefered), but I was just curious before I add this.

 

I'm sorry to be a pain, but this still isn't very clear.

Can we have sub.mydomain.com point to www.mydomain.com/sub/ as though www.mydomain.com/sub/ is the root of the site?

I suppose what I'm asking here is can we use subdomains to host multiple sites on our webspace?

 

But surely that means that any graphic or document that is referenced with an absolute path must prefix the path with the /sub?

For instance, a site may have a folder called 'images' in its root, but in order to reference these files the path must read /sub/images/image.gif because the actual root of the site is still that of your domain?

If this is the case it begs the question; why would anyone pay an additional $5 per month when you can achieve the same thing with a $13 domain registration at enom?

Thanks!
M