Windows CE 5.0 program development for smart device using VS2008

I'm trying to develop a program for my car's smartdevice. The OS on the smartdevice is a very very simplified Windows CE 5.0 version with .NET 2.0 (3.5 doesn't work). I can push the NAVIGATION button on the device which (with a trick) brings me to the desktop. via the inserted SD card I can start just a few simple programs which I have downloaded from the internet (besides the original navigation program). I have tried to develop a C# form application in VS 2008 for drawing a very simple line. The form has just one button and one picturebox (pbDrawing). The C# code for the button is:
   Pen pencil= new Pen(Color.Blue, 4);
   Graphics paper= pbDrawing.CreateGraphics();
   paper.DrawLine(pencil, 10, 10, 250, 0);

The projecttype is set to "smartdevice" and the .NET is set to "2.0". It builds successfully and it does run perfect on my laptop, but it just won't work on the smartdevice in my car. What I noticed is that CreateGraphics is not shown by intellisense under .NET 2.0. But if I type the same statements under .NET 3.5 then intellisense does show CreateGraphics. Anyhow both versions of the programs do not run on my smartdevice. Are you able to help me to find the cause? I'm happy to share any further information you need.