Mt Whitney Zone Forums General Discussion Question about permit - Overnight Exiting Mt Whitney

I am trying to do something similar, but I'm having a different issue. On a trip from Cotton Wood Lake to Whitney Portal, I clicked on "visiting Mt. Whitney" option and my last day is a Trail Camp. All that is fine, but I cannot find Whitney Portal as the exit point. The closest I get to is North Fork of Lone Pine Creek. Am I not able to exit through the main trail?