Enabling Viewers in Outlook

[GraeagleBill]

I downloaded the viewer for file type psd,


Adobe PhotoShop file. I can save the psd
file attachment and open it, but I cannot
get Outlook 2010 to recognize that the
viewer exists and should be employed when
I attempt to "preview" the attachment
directly from within Outlook. I just get
the error message that there is no viewer
available for that file type.

How do I get Outlook to recognize the viewer?

Thanks,
Bill