DocuSign：使用自定义字段发送模板

Question

我正在使用https://github.com/docusign/docuSign-csharp-client

中的DocuSign.eSign库

我创建了一个EnvelopeDefinition：

var envDef = new EnvelopeDefinition()
    {
        CustomFields = new CustomFields()
            {
                TextCustomFields = new List<TextCustomField>()
                    {
                        new TextCustomField()
                            {
                                FieldId = "d9d584f6-0a3a-40df-b94f-407c1a90c87d",
                                Name = "A.LoanNumber",
                                Required = "true",
                                Show = "true",
                                Value = "1234567890",
                            },
                    },
            },
        EmailBlurb = "Don't panic! This is only a template test.",
        EmailSubject = "Template Test...",
        Status = "sent",
        TemplateId = "458407ac-f0a0-44e6-a60b-5126e2d0a8cf",
        TemplateRoles = new List<TemplateRole>()
            {
                new TemplateRole()
                    {
                        AccessCode = "1234",
                        Email = "jjeppson@example.com",
                        Name = "Josh Jeppson",
                        RoleName = "Borrower.1",
                    },
            },
    };

但无论我使用TextCustomField属性的值组合，A.LoanNumber的默认值“Loan Number”都会在结果文档中输出。

信封正确发送，但文档中没有插入/替换任何字段（上面只显示了一个）。

使用指定的库，如何覆盖自定义字段的默认值？