Hi James nice to meet you. My name is Oscar Novoa, I am in a implementation to HANA S/4 version 1510 and I have the same problem trying to create tje Account ID via transaction FI12_HHANK.
How did you solved the creation of ACCOUNT ID ?
This is crazy, all this process to find to create the information in this field. In the past, you can create this ACCOUNT ID manually, right now it is complicate.
If you have any information to help me to solve this ISSUE could be a great help to me.
Best Regards
Oscar Novoa
Note: my email is oscar.novoa17@gmail.com