Hi Joseph,
I was only able to do this in NWBC.
I select the Manage Bank Accounts link, then the account list link.
Click on the account you have created. In my earlier screenshot where it just shows three tabs (General Data, Additional Data, Attachment) there should now be many tabs and there should now be an edit button.
Select the edit button and go to one of the new tabs (I believe it is connectivity). Here is where you add the account ID.
Sorry I can not provide new screenshots but I don't have the authorization now.
The key complication here is causing you to not see it is that you cannot create account ID when you create the account. You must create the account first, than go back to edit the account to get the new tabs. I do feel the tab with the account ID was labeled connectivity. There is a drop down field with something like Remote as one of the options that was required.