How can I create limits of integration in Word 2007's equation editor?

You can specify an empty left bracket with \left. Your specific example would look like this:

\left 1/2 v^2+(u+1)v|_0^u

or after replacements:

├ 1/2 v^2+(u+1)v┤|_0^u

Actually, it's pretty much the same technique you would use in (La)TeX.

Minor nitpick: You should use \dd for the integration d in the formula. This automatically ensures an upright glyph and a small space before the d.

In the Equation's Design tab, click on Bracket and insert the Single Bracket that has a straight line to the left, and its contents go to the right. Click inside its content dotted box and the click on Bracket again but this time choose the Stack Object - the one without parameters. That should get you there. All you have to do now is fill in the bottom and upper boxes. I hope this helps.