Rename Transaction Document

Hi.  Can you tell me if it is possible to change a template document name for a new transaction, and if so how this can be done?

e.g.

            Form form = new Form("FormName");

            String templateIDStr = form.TemplateID;
            PackageId templateId = new PackageId(templateIDStr); 

            DocumentPackage template = client.GetPackage(templateId);

            string phSignerID = template.Placeholders.Where(p => p.PlaceholderName == "Signer1").First().Id;

            DocumentPackage package = PackageBuilder.NewPackageNamed(packageName)
                    .WithEmailMessage(emailMsg)
                    .WithSenderInfo(SenderInfoBuilder.NewSenderInfo(senderEmail))
                    .WithSigner(SignerBuilder.NewSignerWithEmail(member.EmailAddress)
                        .WithFirstName(member.FirstName)
                        .WithLastName(member.LastName).Replacing(new Placeholder(phSignerID))
                        .WithTitle(member.Title)
                        .WithCompany(member.Company)
                    )
                .Build();

            PackageId packageID = client.CreatePackageFromTemplate(templateId, package);

            DocumentPackage packageDoc = client.GetPackage(packageID);

            String documentName = form.TemplateDocument;
            Document document = packageDoc.GetDocument(documentName);
            document.Name = "The New Document Name";   //THIS DOESN'T WORK

Thanks