You need to do TT in bank, even 內地e個人都係用中國銀行. It is because China is out of the local bank's network. It will cost you around HKD250-300 bank charge. If you want the bank help you process the TT faster, you need to pay extra HKD50.
However, please notice that 內地e個人 maybe need to wait a few days after you applied the TT because the bank in china need to do lots of progress. As you know, they are not as efficient as HK.