In BitShares 2 your transactions gets and id once included into the blockchain. There actually is no "txhash".
The id is of the form 1.11.x
something like this:
locked >>> get_object 1.11.1000
get_object 1.11.1000
[{
"id": "1.11.1000",
"op": [
37,{
"fee": {
"amount": 0,
"asset_id": "1.3.0"
},
"deposit_to_account": "1.2.11268",
"balance_to_claim": "1.15.28529",
"balance_owner_key": "BTS8jcFd3ZNYvW11Sh2uYivWQb17Yd2zuxe7Ee4EDag9gjA9YqSJH",
"total_claimed": {
"amount": 1199997594,
"asset_id": "1.3.0"
}
}
],
"result": [
0,{}
],
"block_num": 6073,
"trx_in_block": 0,
"op_in_trx": 8,
"virtual_op": 32500
}
]
and there is no way of known the id before it has been included in a block .. thus the callback ..