var newRecords = [];
        var c = new sforce.SObject("Service_Order__c");
        c.id ="{!Service_Order__c.Id}";
        c.Payment_1_Invoice__c = {!Service_Order__c.Invoice_Ref_1__c};
        c.Invoice_Date_1__c = {!Service_Order__c.Scheduled_Payment_Date_1__c};
        newRecords.push(c);
        result = sforce.connection.update(newRecords);
        window.location.reload();

faultstring:''0.009915716410510659' is not a valid value for the type xsd:date'

faultstring:''2/1/2017' is not a valid value for the type xsd:date'