title: Do periodicalTask every 5 minutes
body: <p>I want to use PeriodicAgent and do something in backround, but the default interval for PeriodAgent is 30 mins, which is too long for my app. Is there any way (in wp7.0 or above) to change the interval?</p>
  
  <p>Thank you in advance.</p>
  
  <p>-Aaron</p>