Re: ECC integration of "Taxes"

Very high level view:

Question 1: are you speaking about the integration ERP ---> C4C? If yes, you can create one unique ws that combines account and taxes data, even if this is not needed (you can reuse the standard account ws and create only the custom ws for taxes)

Question 2: you have different options:

- for the taxes you create an MDR (mass data run) that will call the web service on HCI side after a delay.

or

- You can call immediatly the custom ws on HCI side, but when HCI sends the idoc to the ABAP system, you can handle this idoc with a custom inbound Function Module that will wait till the account is created.