Colin Moock comments in a Technote on using special characters in ActionScript. The post comments on Flash MX, ways to Escape characters and mentions the HEX and UNICODE equivalents for the copyright, registered trademark, curly single and double quotation marks symbol for left and right.
Unicode is the universal character code that provides a unique number identifier for every character or symbol, in any language, platform or program. More information on Unicode can be found in the Unicode website.