Imports a private key from a file.
procedure ImportKeyFromFile(Path: String; Password: String);
Use this method to load a private key from a file. Provide the encryption password via the Password parameter. The Password parameter is optional. If it is omitted and it is later discovered that the key is password-encrypted, the PasswordNeeded event will be fired to request it. If there is an initialized certificate or certificate request object inside the manager, the loaded key gets associated with that object. This method supports keys in DER, PEM, PKCS#8, and PVK formats.