I\'m using Forms authentication and I would like to make use of roles, can I somehow set the role of the user without Membership ?
A simple way to do it is to store the list of roles in the authentication ticket when the user is authenticated. Then for every request (Application_AuthenticateRequest method of the global.asax file) you extract the roles, add them to a GenericPrincipal object and set the Httpcontext.User property.
Your User.IsInRole("role") and [AuthorizeAttribute(Roles="role")] will then work as normal.
See this answer for code detailing how to do it.