1. You can, but you need to do it using the pet palette option after the S/E is placed.
2. You can't use polylines or splines to create
symbolic
fills, only lines, arc/circles, hotspots anf fills. You may also try using the Zoom function within the Fill Types dialog to better see your fill.
3. There's an overly long and complex
explanation for this. I wish it was much a simpler WYSIWYG interface!
Cheers,
Link.