Keywords Don't Work in Illustrator Files?

Hi, we generate tons of illustrations using Illustrator CC, so I started creating a keyword list in Bridge to make searching for stuff easier (the purpose of keywords, of course). I didn't want to get too far in without testing, so I applied a single keyword to an .ai file and searched. No result. It won't find the file. However, if I apply the same keyword to any raster image (.png, .jpg, etc.) it finds the file no problem. 

I didn't get any errors when I applied the keyword to the file, and it shows up when I view the Metadata in Bridge. So why won't search find it? Leads me to believe that .ai vector files won't work with keywords. True, or am I just doing something wrong?

Any help is greatly appreciated!