A general solution for creating icons involves using the Alias renderer. A model of the icon you wish to represent would be created within Alias. Use the Render -> Globals -> Image File Output option to set the Format and Depth Format to ALIAS. Then set the X and Y resolution to 32 for small icons or 48 for medium icons. Render the image and then use that image as the icon for the plug-in. This solution will work on any platform.