IRoleStore is used if you need do a custom provider. if you are in a soe you can use rest admin http://resources.arcgis.com/en/help/server-admin-api/security.html
🙂
Yes, I know that with the REST Interface I could get the users and roles. My question was more related to the Interface iRoleStore and how to get it. I mean if we can do it by REST then there MUST be an ArcObjects Interface to use.