iOS Question post 2 image with httputils

Dim job As HttpJob
                job.Initialize("job", Me)
                Dim fd1,fd2 As MultipartFileData
                fd1.Initialize
                fd1.Dir = File.DirDocuments
                fd1.FileName = "card.png"
                fd1.KeyName = "card"
                fd1.ContentType = "application/octet-stream"
               
                fd2.Initialize
                fd2.Dir = File.DirDocuments
                fd2.FileName = "sign.png"
                fd2.KeyName = "sign"
                fd2.ContentType = "application/octet-stream"
               
                job.PostMultipart("MyURL", CreateMap("id": File.ReadString(File.DirDocuments,"id")), Array(fd1,fd2))
                job.JobName = "upload"