If you are having difficulty using Microsoft's United States-International Keyboard in Windows 7 and SED Bootguard please refer to the following support article from Microsoft:
How to use the United States-International keyboard layout in Windows 7, in Windows Vista, and in Windows XP http://support.microsoft.com/kb/306560
Symantec Encryption Desktop's (SED) Boot Guard functions slightly different than Windows. Please familiarize yourself with the following If you are defaulted to use the US International keyboard in Windows, you will be defaulted to the US International keyboard when you encrypt the disk using SED. You will then need to keep in mind the functions of certain special characters uniquely used in the US International keyboard.
Creating international characters