As long as you remember the names of the accents, it's not a problem.
Personally, I use alt + numpad to do my accents; 'Kishi's û is alt+0251, é is alt+0233, etc., but that's a habit I formed from going to boards where HTML is disabled. Here, you can use ampersand + letter + accent type + semicolon.
é gives you é, â gives you â, ö gives ö, and 'kishi's û is û.
Edit: Also try [ u^] without the space in it.
Testing: [u^]
