From the Steem network
transfer to register
memo field is
steem-pubkey or bts-pubkey or bts-account-name:requested-steem-account-name:optional-refund-memo
from the BitShares network
transfer to steem-register
memo is
steem-pubkey or bts-pubkey or bts-account-name:requested-steem-account-name
There is no auto refund feature on the BitShares network at this time.