How do I set up instrument lists by posting isins to the DSS REST API please?

What does work is importing a list (csv) like

ISN,<actual isin 1>

ISN,<actual isin 2>

Etc.

via the GUI. However GUI isn’t feasible for the (fairly big) set of isins im interested in.

The relevant API call

https://hosted.datascopeapi.reuters.com/RestApi/v1/Extractions/InstrumentLists(\'0x06cf46cdfdf1011b\')/ThomsonReuters.Dss.Api.Extractions.InstrumentListAppendIdentifiers

doesn’t work. I'm Getting the error

'{"error":{"message":"Malformed request payload: Error while parsing an enum value: Requested value \'Isn\' was not found."}}'.

(I was trying IdentifierType “ISN”, “Isn”, “ISIN”, “Isin” – the API help suggests “ISIN” or “Isin”. Neither works.

The list id does exist, it’s called “ez_0”.)