Control of SmartNavigation?

[haile]

I have a page with three panels, Step1, Step2, Step3. Step1 is very large,
so I want SmartNavigation on. When user proceeds to Step2, I want it turned
off. However, two round trips are required, so SmartNavigation does not get
turned off until Step3! Any way to make this work?

ASPX:

<aspanel id=pnlStep1 ...>
<asp:button id=btnNext1 text="Next"></asp:button>
</aspanel>
<aspanel id=pnlStep2 ...>
<asp:button id=btnNext2 text="Next"></asp:button>
</aspanel>
<aspanel id=pnlStep3 ...>
<asp:button id=btnNext3 text="Next"></asp:button>
</aspanel>

C# CodeBehind:

// in page load, (!IsPostBack), Page.SmartNavigation is initially set on.

protected void btnNext1_Clicked(o,e)
{
Page.SmartNavigation = false; // does not take effect on this round trip!
pnlStep1.Visible = false;
pnlStep2.Visible = true;
}
protected void btnNext2_Clicked(o,e)
{
pnlStep2.Visible = false;
pnlStep3.Visible = true;
}
// Only on a subsequent round trip, for example to display pnlStep3, does
SmartNavigation go off.

So what is the deal with SmartNavigation? Is it one of those things that is
determined on InitComponent, before subsequent events fire, or is it
something we are supposed to be able to control?

Any help would be appreciated.
Haile