SETUP_EXTERNAL_USER_ACCESS_MANAGE SETUP Endpoint
  /rpc/setup/?method=SETUP_EXTERNAL_USER_ACCESS_MANAGE  
  Object: 267. Click here for more information.  
  PARAMETERS TYPE  
  DataReturn Text A comma delimited list of advanced search fields to be returned after a successful save
  Id Numeric  
  Remove Numeric Pass '1' to remove the item
       
  AcceptSupport Text (1) Y/N [Default]
  AuthenticationLevelMinimum Numeric What is the minimum level of authentication that the target user must have to be able to switch into your space. 1 = Standard [default], 2 = Logon Key, 3 = Logon Key and Password Code
  Notes Text (2000)  
  TargetUser Numeric Mandatory for all but Type = 3. The user in your space that they are impersonating
  Type Numeric 2=Limited Access to My Data & Share Documents [Default],3=Support,5=Pre-Authorisation

If you pass type=5 it returns the code that you will need for the second stage of authorisation
  UnrestrictedAccess Text (1) Y /N [Default]
  UserGuid Text Mandatory. The guid of the external User. Depending on the Type, they will need the appropriate CanSwitchIntoOtherSpaces / CanAcceptSupportIssues
  RETURN  
  id