Noob: Is there a "root" for IIS virtual dir?

I’m attempting to install a rails app as well as typo to virtual
directories of the same web site in IIS 6.

Problem is that URL’s in the browser page are missing virtual directory

For example, with typo installed in “/blog”.
Typo link in browser: http://hostname/articles/category/mycategory
Typo link should say: http://hostname/blog/articles/category/mycategory

Have I missed a configuration setting (within rails)?

Many web application configurations have a “root” to set a base URL, in
this case it would be “/blog”. Is that available in rails?