DocuSign API Replace template document but keep fields - php

Question

I want to use the existing fields from a server template over another document.
At first I tried attaching the document at the same level as inline/server.
If I have the signer defined it gives me a 400 error, if I leave it off (did by accident) it completely wipes out the fields and shows the attached document.
Second I tried attaching the document to the inline template but that results in the attached document not appearing, it just operates like normal.
update
After adding additional debugging and research I now know that attaching it to the inline template was incorrect. After adding debug to read the 400 response I am getting this error:
"The DocumentId specified in the tab element does not refer to a document in this envelope. Tab refers to DocumentId 32475214 which is not present."
DocumentId is being set to 1 which is apparently wrong.
Which led me to this question on SO. In which a comment mentions that the ID kicked back from the 400 should be used.
After I hard coded this ID I see the replacement operation is a success!
However I now need to find a way find and to plug that value in programatically.
Detail
I am using the DocuSign php sdk to help me build the data structure and access the api.

Answer 1

Use the listTemplateDocuments API to retrieve the documentId for the template.
The documentId retrieved in the above step should be used in the CompositeTemplate of CreateEnvelope request
{
"emailSubject": "Tabs should remain from the Server Template",
"status": "sent",
"compositeTemplates": [
{
"document": {
"documentId": "<document Id>", //Use the documentId retrieved using the listTemplateDocuments api
"name": "Replaced Document",
"fileExtension": "txt",
"documentBase64": "RG9jIFRXTyBUV08gVFdP"
},
"serverTemplates": [
{
"sequence": "1",
"templateId": "<Server Template Id Here>"
}
]
}
]
}