code: @Nonnull
    public AS2ClientBuilder setKeyStore (@Nullable final IKeyStoreType aKeyStoreType,
                                         @Nullable final File aKeyStoreFile,
                                         @Nullable final String sKeyStorePassword)
    {
      m_aKeyStoreType = aKeyStoreType;
      m_aKeyStoreFile = aKeyStoreFile;
      m_sKeyStorePassword = sKeyStorePassword;
      return this;
    }
docs: Set the key store type, file and password for the AS2 client. The key store
  must be an existing containing at least the key alias of the sender (see
  {@link #setSenderAS2ID(String)}). The key store file must be writable as
  dynamically certificates of partners are added.
  
  @param aKeyStoreType
  The key store type. May not be <code>null</code>.
  @param aKeyStoreFile
  The existing key store file. Must exist and may not be
  <code>null</code>.
  @param sKeyStorePassword
  The password to the key store. May not be <code>null</code> but
  empty.
  @return this for chaining