Fluent Nhibernate Enum Mapping

I have some problem with enum mapping in fluent NHibernate. I know this question has been asked many times but I couldn't find any solution that worked for me. I'm newbie in NHibernate and it looks like I may have missed something simple and stupid. Here is my code.

public class DBPublication{    public virtual int pub_id { get; set; }    public virtual PublicationStatuses status { get; set; }    ...}public enum PublicationStatuses {    on_moderation,    active,    ...}public class DBPublicationMap : ClassMap<DBPublication>{    public DBPublicationMap()    {        Table("content.publications");        Id(x => x.pub_id).GeneratedBy.Sequence("content.pub_sq");                   Map(x => x.status);        ...    }}

postgres enum type

CREATE TYPE content.enum_publication_status AS ENUM('on_moderation', 'active', ...);

but when I try to save, postgres throws this

column "status" is of type content.enum_publication_status but expression is of type text

any suggestion?