GetScrollInfo not working for WebBrowser

[Mohit]

Hi all,
I am using GetScrollInfo on webbrowser control of .Net Framework
2.0. I am not getting the scrolling bar info. Following is what I am
doing:

[DllImport("user32.dll", SetLastError = true)]
private static extern int GetScrollInfo(IntPtr hWnd, int n,
ref ScrollInfoStruct lpScrollInfo);

private struct ScrollInfoStruct
{
public int cbSize;
public int fMask;
public int nMin;
public int nMax;
public int nPage;
public int nPos;
public int nTrackPos;
}

ScrollInfoStruct si = new ScrollInfoStruct();
si.cbSize = Marshal.SizeOf(si);
si.fMask = (int)SIF_RANGE;
GetScrollInfo(this.wbTest.Handle, SB_VERT, ref si);

Is there something which I am missing???
Thanks in advance!!!