Nike + Intervals?

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I've been using RunKeeper for a while to keep track of runs. One of the things I like about it is that I can create what they call Workouts. I can go in and say, for example, 5 minute warmup, 19 minutes running, 2 minutes walking, 18 minutes running, 2 minutes walking, 18 minutes running, 5 minute cool down." When you hit that time, it gives you an audio prompt to change.

I'm considering making the change to Nike+ Running's app because more of my friends are on that. However, it doesn't seem that Nike+ lets you do that beyond their "1 minute, 5 minute, 10 minute" options for audio prompts. Am I missing a feature? Does Nike+ let you do that?

I know it has the COACH feature now, but being able to adjust my workouts day to day is super helpful on RunKeeper.