Serius Sattelite Install

Hello all,
 
I just picked up a 2008 Mazda5 GT with DVD nav and Entertainment System. As an afterthought we decided we wanted the serius sattelite radio as well. I didn't want to spend $500 to have the dealer install it so I decided to do it myself. I found the right Serius model and the accompanying install kit and started to follow the install instructions everything was going fine until it came time to pull out the climate control unit...
 
The instructions say that there are only 2 screws holding in the Climate Control unit underneath the NAV system. But after I pulled those 2 screws out the unit would still not come loose and I didn't want to force it. The instructions don't say anything about any hidden clips or anything else other than those two screws. But there has got to be something still holding it in... Does anyone here know how to properly remove that unit? Or where I could find the answer?
 
Thanks for your time!

Hi. Sorry I can't help with the install as I just bought my 5 and haven't tried anything yet. I am interested in the Sirius radio though, and don't want to pay the dealer for it. What model did you find that works with the MAzda. Is it the SCC1?

http://shop.sirius.com/edealinv/servlet/ExecMacro?nurl=control/StoreItem.vm&ctl_nbr=2640&siId=2482698&catParentID=24750&scId=24750