Hi,
The CC and BCC Reciever addresses are stored in the email header.
When you get a mail with the class you get an array.
$array = array( "<HEADER>",
                "a header line",
                "CC: Hans Mustermann <
[email protected]>"
                "and soon",
                "</HEADER>" );
while( ($buf = next($array)) != "</HEADER>" )
{
    if( preg_match("/^(CC|BCC)/i",$buf) )
    {
        // Now you have the line
    }
}
Good Luck