// Read file contents into array 'buf'
sizeBuf = in.read(buf);  
in.close();

//Generate a signature 'b' with a Private Key
s.update(buf);
byte[] b = s.sign();

//Create a StringBuffer and add to it the original XML file and the signature
StringBuffer sb = new StringBuffer(new String(buf,0,sizeBuf-4));
sb.append(new sun.misc.BASE64Encoder().encode(b));
sb.append(new String(buf, sizeBuf-4, 4));

//Read the buffer and insert into Tamino
StringReader sr = new StringReader(sb.toString());
xmlObject.readFrom(sr);
xmlObjectAccessor.insert( xmlObject );