C# Transparency in XP

I have a little splash window:

public partial class Splash : Form
{

  bool painted = false;

  public Splash()
  {
    InitializeComponent();
  }

  protected override void OnPaint(PaintEventArgs e)
  {
    //
  }

  protected override void OnPaintBackgroun开发者_StackOverflow中文版d(PaintEventArgs e)
  {
    if (painted)
        return;

    Graphics gfx = e.Graphics;
    gfx.DrawImage(Properties.Resources.Splash, ClientRectangle);
    painted = true;
  }
}

Properties.Resources.Splash is a PNG with alpha, and displays beautifully on my Windows 7 development computer.

On the Windows XP target computers, however, there is no transparency; instead, the background of the image is black.

I know it's possible to display a transparent splash window in XP because I have seen it before. Is it possible to do it in .net? If so, how?

It can be done with WS_EX_LAYERED but requires some efforts and some P/Invoke: http://msdn.microsoft.com/en-us/library/ms997507.aspx

Also there is an older article here but don't know if it's still valid: http://www.codeproject.com/KB/cs/transparentwindowsincsharp.aspx