I can suggest you to manage the visibility of the child tabs, when the "Final Estimate" tab is clicked. I have prepared a sample project for you, demonstrating how you could implement the desired functionality. Please find the sample attached.
Note : dll files are removed from the attachment.
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed