namespace xxx.hh.Business.Entities
{
    public class hhDbRoleProvider : IRoleProvider
    {
        public IRole New(string roleName)
        {
            return new Role(this)
            {
                RoleName = roleName,
                Description = string.Empty
            };
        }
        

        public IEnumerable RetrieveAllRoles()
        {
            
             List<IRole> roles = new List<IRole>();

            using (IDataReaderEnumerable dalRoles = Role.RetrieveAll())
                foreach (Role dalRole in dalRoles)
                    roles.Add(new Role(dalRole));


            return roles;
        }


    }
}

Class2 (HHRoleProvider)

namespace xxx.hh.Common.Roles
{
    class HHRoleProvider : RoleProviderBase
    {
        public override Configuration.Roles.Role[] GetRoles()
        {
            // Grab all the roles from the DB
            hhDbRoleProvider roleProvider;
            
           List<xxx.BusinessInterfaces.Security.IRole> hhRoles = roleProvider.RetrieveAllRoles();
....

The error is on the last line and I cannot figure out how the hell to get it to be "happy":

Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<xxx.BusinessInterfaces.Security.IRole>' to 'System.Collections.Generic.List<xxx.BusinessInterfaces.Security.IRole>'. An explicit conversion exists (are you missing a cast?)