UMAPI - Create BusinessID?

[jamianw85609580]

The documentation for the user management api details adding an AdobeID, and creating EnterpriseID or FederatedID.  All my user accounts are of the identity type: BusinessID when viewed in the web console, but userType: adobeID when returned from the get user UMAPI endpoint.  When creating a new user via the UMAPI - am I supposed to add an AdobeID, create an EnterpriseID, or is there an undocumented endpoint for creating a BusinessID user account?  I've tried creating a test user with the "do" action of "createBusinessID", but recieved a 400 bad request. 

The UMAPI seems to be neglected what with the deprecated endpoints with no replacements, the notification stating that an update will be provided by end of 2017, and the Github samples dating to 2017/18 (assuming when the UMAPI was created).