CUPI create user - externalserviceaccounts

I might be missing something, but I am having an issue setting up an external service (exchange) account for a newly imported user using the CUPI API.

The wiki explains that you get the user object-id, then go to '/vmrest/users/<object-id>/externalserviceaccounts' to get the object ID of the users external service account(s).

Since this is a new user, the result I get is:

<ExternalServiceAccounts total="0"/>

This is correct, the user doesn't have any external accounts yet, but how to I go about generating/creating one without knowing this ExternalServiceAccounts object-id?

you can get the list of external services that are configured on the server:

https://<server name>/vmrest/externalservices

the type and object ID of the service (i.e. O365 integration) can be fetched from there.

When you get stuck remember that the (servername)/vmrest/schema is the first place to stop - the full schema breakdown for the REST API can be found there for the version of Connection you're against.