Adobe ACROBAT READER 7.0 Manual page 156

Using third-party digital IDs
When you sign or validate a document, you can use the Default Certificate Security, the
Windows Certificate Security, or a third-party security method. When you install a third-
party signature provider, new menu commands may appear. Use these commands instead
of, or in addition to, the Manage Digital IDs commands. In addition, a Third-Party
Preferences submenu may appear on the Edit menu (Windows) or on the Adobe Reader
menu (Mac OS) so that you can change the provider's preference settings.
To specify a third-party security method:
1. If necessary, install a third-party signature provider.
2. Choose Edit > Preferences (Windows) or Adobe Reader > Preferences (Mac OS), and
then click Security.
3. Click Advanced Preferences.
4. Choose the provider from the Default Method To Use When Signing And Encrypting
Documents menu, which lists all security methods installed in the Reader Plug-ins folder.
5. Click OK.