Don't know about the Al remote and Office 2011, but I have the white plastic Apple remote that came with my late 2007 MacBook Pro. If I point it at my iMac i7 with Office 2008, the left/right buttons on the remote act as forward/back buttons in PowerPoint. The center "select" control seems to act as a mouse-click.
Has the remote been "paired" to your computer? If you look at the instructions taht came with it, there is a simple procedure hhtat dedicates it to one Mac, insteda of activating every IR-equipped Mac in range (like mine does).