The problem is when you set NavigateUrl of the item the control loses its state. That's why you need to find a way to persist the value of the selected node as an attribute or cookie and expand it properly after the redirect occurs reading the cookie value. Please take a look at the attached template which you can map for your Navigation control in Sitefinity. I have attached a short video demonstrating how to set this up and a demo of the result. Please inform us if you have any additional questions.
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