code: function(SOAPEnvelope, siteDataOperation) {
              var siteDataOp = siteDataOperation.substring(8);
              SOAPEnvelope.opheader = SOAPEnvelope.opheader.replace(siteDataOperation, siteDataOp);
              SOAPEnvelope.opfooter = SOAPEnvelope.opfooter.replace(siteDataOperation, siteDataOp);
              return SOAPEnvelope;
          }
docs: The SiteData operations have the same names as other Web Service operations. To make them easy to call and unique, I'm using the SiteData prefix on their names. This function replaces that name with the right name in the SPServices.SOAPEnvelope.