Pointing 3rd party domain to addon domain

I have a Shared plan w inmotion. I created an addon domain in my inmotion cpanel and the addon domain is marketing.mmparrish.com (which is a subdomain of mmparrish.com which is another website altogether, which I do not host). Our IT guy has control of the domain (mmparrish.com) and has now pointed marketing.mmparrish.com to 74.124.210.242 (by using an A Record in his domain panel) because I thought that would make the site go live. But it didn't. I do have my Addon Domain setup correctly, I think... I have it pointed to the root folder I chose, which is inside of my public_html folder. So to make a long story short(er) lol, I need marketing.mmparrish.com to point to here (my temp address) http://ecbiz230.inmotionhosting.com/~joshal5/mmmp/ or here, with is just my primary domain with my subfolder: http://joshalterman.com/mmmp/ Do I need to make a change in Cpanel, or does my IT guy need to do something differently? Or both?