Symfony2: how can I make a or just

My buttons from the Symfony form component come out as:

<button type="button">Submit</button>

Of course, this doesn't submit the form.

What I'd like is:

<button type="button">Submit</button>
// or
<button>Submit</button>

I'd rather not use an <input type="submit"> so I have more control over the look of the button.