You can use the /raw command to send raw data to the server. You can either put this into perform or send them on *:connect. I think you only need one of these though but I suggest using both for most data.
/raw CAP REQ :twitch.tv/commands
/raw CAP REQ :twitch.tv/membership
Edit: add /tags too. Pretty neat info on users when they send something as second poster already said :).