You really need to get the proper grommets and eyelets for the servo. That "little" piece of rubber and brass is what protects your servo from failure in flight. The grommets and eyelets are designed to isolate the servo from the vibration that occurs to the airframe in flight. Without this isolation the electronics in the servo can be quickly damaged and fail. Also, the vibration can also put stress and wear on the geartrain of the servo and cause it to fail. With this in mind, the cost of the grommets and eyelets are very cheap in comparison to the cost of losing a plane. Trust me here, these are something you do not want to skimp or "make do" on.

If I remember correctly you have a Futaba radio. So going off of that approximately $10 will give you enough grommets and eyelets to do 5 servos.
[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXH438&P=7]Futaba eyelets[/link]
[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXH374&P=7]Futaba grommets[/link]

Ken