In an agreement with the others, I see no possible explanation that you couldn't store a standard ASCII character. The character "©" is no different from the character "a". Both have ASCII values under 255, so it's not even extended.
If you need to type them, press:
Alt+0174 = ®
Alt+0153 = ™
Alt+0169 = ©
Make sure the numbers are typed on the number pad. If you want to use these without typing the ASCII character in HTML, try: ®, ™, and ©.