Why doesn't latest version of pdf have a visible signature, only blank fields

I'm C# user and tried both createUrlWidget and createPersonalUrlWidget to send a test document, and after it signed by signer, I used both getLatestDocument and getDocuments, but only get a pdf without seeing signature like this:

I can get signed doc using the link in email sent to signer:

So, I'm confused, can anybody answer me where did I missed?

1. the method I used to create url widget:

public static bool createUrlWidget(string fileName)

        {

            FileStream file = File.OpenRead(fileName);

            com.echosign.secure.FileInfo[] fileInfos = new com.echosign.secure.FileInfo[1];

            fileInfos[0] = new com.echosign.secure.FileInfo(fileName, null, file);

            SenderInfo senderInfo = null;

            //string[] recipients = new string[1];

            //recipients[0] = recipient;

            RecipientInfo[] recipients = new RecipientInfo[1];

            recipients[0] = new RecipientInfo();

            recipients[0].email = "myemail@hotmail.com";

            RecipientRole role = new RecipientRole();

            role = RecipientRole.SIGNER;

            recipients[0].role = role;

            WidgetCreationInfo widgetInfo = new WidgetCreationInfo();

            widgetInfo.name = "Test Docx";

            widgetInfo.fileInfos = fileInfos;

            //widgetInfo.counterSigners = recipients;

            WidgetPersonalizationInfo personInfo = new WidgetPersonalizationInfo();

            personInfo.comment = "Test sign of doc";

            personInfo.email = recipients[0].email;

            personInfo.reusable = false;

            UrlWidgetCreationResult result = ES.createPersonalUrlWidget(APIKey, senderInfo, widgetInfo, personInfo);// ES.createUrlWidget(APIKey, senderInfo, widgetInfo);

            if (result.success)

            {

                DocumentKey2 = result.documentKey;

                urlWidgetReturn = result.url;

            }

            else

                return false;

            return true;

        }

2. the method I get the documents, there's only 1 content in returned DocumentContent[]:

public static void getDocuments(string documentKey)

        {

            GetDocumentsOptions opts = new GetDocumentsOptions();

            //opts.versionKey = "latest version";

            //opts.participantEmail = "myemail@hotmail.com";

            opts.combine = true;

            opts.attachSupportingDocuments = true;

            GetDocumentsResult result  = ES.getDocuments(APIKey, documentKey, opts);

            if (result.success)

            {

                DocumentContent[] contents = result.documents;

                foreach (DocumentContent dc in contents)

                {

                    FileStream file = File.OpenWrite(string.Format("c:\\{0}.pdf", Guid.NewGuid()));

                    file.Write(dc.bytes, 0, dc.bytes.Length);

                }

            }

        }

This is my first time to use this api, so maybe I missed some important steps to cause this. I appreciate anybody which could see this and help me.

Thanks a lot!

Kenny