If you want your email to go to your account and somewhere else, you have to use email filters . On mailserv You can't login to a mailserv account. The best way to forward email on mailserv is to use email filters .
Email Filters .forward only redirects email to other accounts.
If you want to do anything fancier than that, in particular if you want your email to go to your account and somewhere else, you have to use procmail email filters.