you have to create a .fti file.
afaik the only way to do that is to use the fti exporter in the bonus tools. With that you can create a snapshot of your object in the viewport.
QUOTE
ftiExport: This commands generates FTI images for hyperShade icons.
The icon should be created in the front window from a single polygon mesh. Every edge on the mesh will
be a line in the final icon. Coloring for the icon is taken from the color attribute of the shader on each face in the mesh.
Output Directory: The directory to write the image to.
File Name: The name of the image.
Extra Space: Amount of boder space to put around the image.
To use, Bonus Game->FTI Export.
Note: The easiest way to view the image is to give it the name of an existing icon, restart
Maya and then create the node associated with the icon.
if you have to much time you can create such a file manually, but thats no fun I guess