EOS Rio team is working hard on the 0.7.3, but you can already use SimplEOS for proxy voting. It is quite simple, just follows these steps:
1- Go to “Contracts” section and search for “eosio”. Click on it.
2- Choose “voteproducer” on the contract actions and fill your account name (the same you are currently using) and the proxy account, leave the “PRODUCERS” field empty
3- Put your password …
… and congratulations, you have just proxied your vote!
We made products with love and hard work. Thanks for using SimplEOS and sending us feedback :)