How do I use uploaddoc parameter when using the Create Task method of the Project API?

How do I use uploaddoc parameter when using the Create Task method of the Project API?

I'm trying to create a task and attach a file using the Create Task method of the Project API.

The uploaddoc parameter is of type "file".  There is no sample code on how to use the uploaddoc parameter.

I assume the uploaddoc file parameter is looking for a binary file, but I'm unsure how to specify this in the code.

I've been able to use other methods of the API correctly.

The code below successfully creates the new task and completes without error, but there is no file attached to the task. 

Please provide examples of how to use the uploaddoc parameter.

Thank you.

FileName := CHSDirectory . "HITRUST Templates\" . FileName
URL := "https://projectsapi.zoho.com/restapi/portal/99999999/projects/" . ProjectID . "/tasks"
Data := URL . "/?authtoken=999999" . "&name=" . TaskName

ADODBObj := ComObjCreate("ADODB.Stream")
ADODBObj.Type := 1
ADODBObj.Open()
ADODBObj.LoadFromFile(FileName) ;Load the contents of the binary file into the Stream
 
WebRequest := ComObjCreate("WinHttp.WinHttpRequest.5.1")
WebRequest.Open("POST",Data)
WebRequest.SetRequestHeader("uploaddoc", FileName, "multipart/form-data")
WebRequest.Send(ADODBObj.Read())

ADODBObj.Close()
JSONString := WebRequest.ResponseText
MsgBox Response  - %JSONString%