Do you have a drawing document active when trying to do the customization? The list of commands in the keyboard shortcuts interface is specific to the document type so those commands won't show for parts or assemblies.
I hope this helps,
Jim, you are correct! Odd thing is that on both system, I only had a model open yet on one I could find the command and on the other not. To make things even more odd, what I posted above showing the command in "Other" and an ampersand in the name, no longer exists where it did last night. But if I open a drawing and look at the commands I get the key assignments to Next and Prior (as shown above from last night) but now they are under category "view" and no longer have the ampersand. I'm marking this corrected and ignoring the oddities.