We need to solidify the latest validator API exposed by the beacon node (active discussion here: https://github.com/ethereum/eth2.0-APIs/issues/12) and implement it in the beacon node. There are stubs API methods/functions in the validator client as of ethereum/trinity#1482.
One important thing to do here is to fetch the Fork data from the beacon node so that the validator client can create the proper BLS domain when making a signature.
We need to solidify the latest validator API exposed by the beacon node (active discussion here: https://github.com/ethereum/eth2.0-APIs/issues/12) and implement it in the beacon node. There are stubs API methods/functions in the validator client as of ethereum/trinity#1482.