I don't think you need Preserve:
eConnectType ect = new eConnectType();
XmlSerializer s = new XmlSerializer(ect.GetType());
eConnectType econnect = new eConnectType();
RQeConnectOutType eConnectouttype = new RQeConnectOutType();
eConnectOut eConnectOut = new eConnectOut();
eConnectMethods entrypoint = new eConnectMethods();
string requesterDoc = String.Empty;
string sconn = String.Empty;
eConnectOut.DOCTYPE = "Customer";
eConnectOut.OUTPUTTYPE = 1;
eConnectOut.INDEX1FROM = "AARONFIT0001";
eConnectOut.INDEX1TO = eConnectOut.INDEX1FROM;
eConnectOut.FORLIST = 1;
eConnectouttype.eConnectOut = eConnectOut;
econnect.RQeConnectOutType = new RQeConnectOutType[1] { eConnectouttype };
[and continue with the example...]