nautilus and gio apps

[Gravis <nautilus adaptivetime com>]

I've written a GTK+ image viewer program (single binary file) that opens
files using GIO.  The program works fine from CLI, like this:

viewer sftp://username domain com/filepath/filename.jpg

When I try to open the same image using nautilus from the same location
using "Open with Other Application..." and select the binary, it just
shows the busy cursor and then stops after about 30 seconds.

Other apps like GIMP can open this file just fine, so do I need to
somehow register the application somehow with Nautilus?  What's the
deal?

-- 
Gravis <nautilus adaptivetime com>