TXT post to DocuSign always gives INVALID_MULTI_PART_REQUEST Boundary terminator not found error - docusignapi

Question

I'm new to this and probably doing something very stupid, but if I carry on like this, I'll be bald!
As a test, I am just trying to send a TXT document for signing to DocuSign via a HTTP Post. I have followed the examples they give (I believe) but what ever I try, I get the same error.
Error:
"INVALID_MULTI_PART_REQUEST",
"message": "An error was found while parsing the multipart request. Boundary terminator '--AAAAA--' was not found in the request.
Ultimately I want to send base64 encoded PDFs but if I cannot even get TXTs to work...
I am using an XML scripting language specific to our in-house application to make the HTTP request, and the process has a diagnostic mode which can dump the request elements out to file to help sort issues: These TXT files are next and I have removed any sensitive data:
REQUESTHEADERS.TXT:
Content-Type: multipart/form-data; boundary=AAAAA
Content-Length: 565
X-DocuSign-Authentication: <DocuSignCredentials> <Username>myemail#myemail.com</Username><Password>mypassword</Password> <IntegratorKey>mykey</IntegratorKey></DocuSignCredentials>
Host: demo.docusign.net
Accept: application/json; charset=UTF-8
Accept-Encoding: identity
User-Agent: Mozilla/3.0 (compatible; Indy Library)
REQUESTDATA.TXT
Content-Type: application/json; charset=UTF-8
Content-Transfer-Encoding: 8bit
Content-Disposition: form-data
{
"status":"created",
"emailSubject":"Test",
"emailBlurb":"This is a test",
"documents":[
{
"name":"test1.txt",
"documentId":"1",
"order":"1"
}
],
"recipients":{
"signers":[
{
"email":"myemail#myemail.com",
"name":"Fred Blogs",
"recipientId":"1"
}
]
}
}
--AAAAA
Content-Type: text/plain; charset=UTF-8
Content-Disposition: file; filename="test1.txt";documentid=1
Please sign this test document
--AAAAA--
Please, if any one can tell me what is wrong I would be very grateful indeed!

Answer 1

It's the formatting of the call, please take note on where I have line breaks and where I do not.
Request
--AAAAA
Content-Type: application/json; charset=UTF-8
Content-Transfer-Encoding: 8bit
Content-Disposition: form-data
{
"status":"created",
"emailSubject":"Test",
"emailBlurb":"This is a test",
"documents":[
{
"name":"test1.txt",
"documentId":"1",
"order":"1"
}
],
"recipients":{
"signers":[
{
"email":"myemail#myemail.com",
"name":"Fred Blogs",
"recipientId":"1"
}
]
}
}
--AAAAA
Content-Type: text/plain; charset=UTF-8
Content-Disposition: file; filename="test1.txt";documentid=1
Please sign this test document
--AAAAA--
Response
{
"envelopeId": "{envelopeId}",
"uri": "/envelopes/{envelopeId}",
"statusDateTime": "2015-02-27T18:53:39.5700000Z",
"status": "created"
}