Well - at the moment I'm doing some research about WCE. Unfortunately I'm limited to use WCE7. I hope most of this goes with 'WCE8' also. Anyway ... Creating a OSDesign.
First, since its WCE7, in Visual Studio 2008, create a new project.
In the New Project dialog, select Platform Builder and OS Design
Click Next, and then and select the Board Support Package. In my case is a ConnectCore i.MX53
Click Next. All the next steps, are supplyer specific. If you want to go with the default setup, just click Finish.
As always, feel free to comment, or ask.