Questions about 1.1 Auras

[Freepaperclips]

I was wondering how 1.1 runewords "always on" auras stack with existing ones. I have a lvl 66 Defiant Avenger and was looking at the new "Exile" runeword, when it occured to me that the "Level 13-16 Defiance Aura When Equipped (varies)" line might overwrite my more powerful slvl 22 aura. Would the "when equipped" constantly renew itself over mine, or would I just have to switch mine off and then on to overwrite it's aura? Exile looks like a great runeword but I can't use it if I have a potental 9 slvl penalty.