1and1 and subdomain

I am using 1and1 for hosting. I have a subdomain “blog.bluelime.com” that I would like to have work as a direct link to my blog, but at the same time have “www.bluelime.com/blog” work. This /blog subdirectory is where the wordpress info has been installed. I tried changing the options on “wordpress address” and “blog address” but neither worked the way I thought they should. Am I doing something incorrectly?