Identity Increment = Greyed Out (actually, All Properties Are Greyed Out)

I am looking to make the primary key auto increment by 1.  I have found by looking around the internet that you need to do this in the Tables -> [Table Name] -> Columns -> [Column Name], Properties window, and I see the "Identity Increment" however all of the properties there are greyed out -- I can't access them. 
Any ideas on how to make this work?

For some background: 
I'm running SQL Server 2005 with Visual Studio 2005.  To create this database, I right-clicked on my project, and went to 'Add SQL Database', I filled in the columns all from within visual studio.