Need help with subdomain domain mapping

I have been using domain mapping no problem with all of our multisite blogs, but this time I have a different scenario and am completely confusing myself on what to do...

I have a domain gallagherebc.com that does not have a blog / site associated to it. It is just the primary domain that we will be creating a bunch of subdomains with to use for our client's (gallagherebc) clients. They have a client (defender) that we have created a site for. Currently that is at defender.bluewaterclick.com. (bluewaterclick.com is our main multisite domain). I got the gallagherebc.com domain, set up the A record that is listed in the IP domain mapping tool (host is gallgherebc.com points to 11.111.111.111) and then parked the domain in our main domain's (bluewaterclick.com) cpanel as I usually do. Then I went to the defender site's domain mapping under tools and put in (custom domain) defender.gallagherebc.com ---> (blog address) defender.bluewaterclick.com. I went into the gallagherebc domain host and created a CNAME of defender and directed it to http://defender.bluewaterclick.com.

It isn't working and I am thinking in circles and can't figure out what I have done wrong, but I am sure it will be obvious to someone else! I also wasn't sure that since we will be having mutiple subdomains to need to do this with, should the * record of gallagherebc.com also be pointed to the IP listed in the domain mapping tool? Do I need to park each of the subdomains also (defender.gallagherebc.com)? Please assist, thanks!!!