Subdomain not mapping correctly

Dear WPMU Dev Team,

Hosted at: Rackspace Cloud
Wordpress Version: 3.5.1 (network install as sub-directories)
Domain Mapping Plugin version: 3.2.2

I currently have a wordpress network installed and hosted at Rackspace Cloud. We are using the wordpress network to create websites for clients, and we need to be able to offer our clients the option to own their own custom domains, in this trial case (www.jillworth.com) and have it point to her sub-directory of our network (www.pagebureau.com/jillworth).

We have made some progress following the following this article:
http://www.shilling.id.au/2011/09/15/wordpress-multisite-on-rackspace-cloud-sites/

As well as your usage guide:
https://premium.wpmudev.org/project/domain-mapping/

Unfortunately, we can get the url to resolve as expected. When you try to visit http://www.jillworth.com, instead of being directed to the sub-directory, you only get directed to pagebureau.com. This leads me to believe that the problem lies with the configuration of the plugin. Here is our process so far:
Installed a wordpress network (as sub-directories) on rackspace cloud.
Created several child sites.
Installed the WPMU Domain Mapping plugin.

Created an A Record for http://www.jillworth.com that points to http://www.pagebureau.com
(this particular domain name is registered through dreamhost)
Then within the rackspace clouds admin area, we set jillworth.com up as an alias of pagebureau.com.
Then we tested that jillworth.com resolves. jillworth.com was resolving to http://www.pagebureau.com.
(at this point, it should be noted that manually typing in the url http://www.pagebureau.com/jillworth would load the correct wordpress child site)
Then, within Jill Worth's site admin area, we added jillworth.com to the domain mapping settings.
(after doing so, manually typing in the url http://www.pagebureau.com/jillworth resolved to http://www.pagebureau.com. Typing in the URL jillworth.com also resolves to http://www.pagebureau.com. The child site is no longer accessible at all. Access to the child site's admin area is possible, but not the actual website.
As far as I can tell from following these steps, adding jillworth.com to the domain mapping plugin should have just worked, and I have no idea what is going wrong.

Could you suggest a course of action so we can fix this together?