How do you get a submit button in the Windows Phone keyboard?

I want the white arrow to appear in my text input boxes so users have a way of forward other than tapping away from the keyboard or using the hardware Back button.

The search fields do this in the system UI. How do I?

Here's my code XAML:

<TextBox x:Name="InputBox" InputScope="Text" AcceptsReturn="True" TextChanged="InputBox_TextChanged"/>

CS:

void InputBox_TextChanged(object sender, KeyEventArgs e)
{
    // e does not have Key property for capturing enter - ??
}

One quick note, I have tried AcceptsReturn as False also.