This is my Umbreon's Set
Umbreon @ Leftovers/Chople Berry
Careful
252 HP / 128 SpD / 128 Spe
Synchronize
~Mean look
~Baton Pass
~Yawn
~Protect
This is how I used it.
Basically Switch Umbreon on the revenge or whenever appropriate and Yawn, they'll most likely switch to a pokemon to counter Umbreon like a fighting type, now the tricky part is to predict whether they'll switch to another pokemon or stay and fight and sleep their current pokemon. If it's the 1st option, use meanlook to trap the switch pokemon if it's the 2nd option, use protect, although it's generally better to use meanlook, you may have lost your umbreon, although he's fairly bulky, if they stay in to attack then it would've fallen asleep.
If they decide not to switch in their pokemon after you switch in umbreon and Yawn, use Yawn again in case they switch on the 2nd turn.
This set has flaws as stated in previous post, such as taunt, U turn and Electric equivilent, Lum Berry, Rest Talkers although Rest Talkers aren't too much of a problem if you have the right pokemon to switch in and set up.
Am I missing something? ah well I've only made one team with Umbreon in it, I've only had sucess using this set.
I dunno but I've had more success with Curselax then Cursebreon. So *Shrugs*