Rulers in CS5

[#1]

I use Illustrator CS5 mainly for adjusting dimensional drawings that comes to me as pdf:s. I "clean them up" so I can use them in our documentation. I wonder if there is a way to set that the rulers are always turned on? I have read a bit here and see that I can (in some way that I don't understand) change this for new drawings, but I open pdf:s, I don't create a new drawing. Is there a way to fix this?

[#2 · Accepted solution]

No, rulers on are a part of the New Document Profile.

PDF files or images opened in Illustrator don't have ruler information.