/**
 * Creates a new instance of DerExternal.
 * See X.690 for more informations about the meaning of these parameters
 * @param directReference The direct reference or <code>null</code> if not set.
 * @param indirectReference The indirect reference or <code>null</code> if not set.
 * @param dataValueDescriptor The data value descriptor or <code>null</code> if not set.
 * @param encoding The encoding to be used for the external data
 * @param externalData The external data
 */
 public DerExternal(DerObjectIdentifier directReference, DerInteger indirectReference, Asn1Object dataValueDescriptor, int encoding, Asn1Object externalData)
 {
     DirectReference = directReference;
     IndirectReference = indirectReference;
     DataValueDescriptor = dataValueDescriptor;
     Encoding = encoding;
     ExternalContent = externalData.ToAsn1Object();
 }