TRM Treasury: Movement interest expense (gross) with MZWST X "Calculate tax" to FI

[Angela2]

In Treasury and Risk Management (TRM), there is a financial transaction in which the interest expense is taxed. The bank also creates an invoice for this with the net interest expense and the VAT amount on the interest expense. There are therefore 2 flows in TRM.

Actually, both transactions should now be posted in FI (transaction TBB1).

Our aim is that two flows (interest expense and tax) are shown in the cash flow in Treasury, but only one gross interest expense is sent to Accounting, so that only one document is created in Accounting and both accounts (interest expense, tax) are shown in one posting record based on the gross amount.

With the badi TPM_ACCIF_TRAC it is not possible to manipulate the amount transferred to FI.

An additional derived flow could perhaps be used to solve this (the actual interest flow is not sent to FI, only the derived flow, which is increased by the tax amount) - however, this derived flow is also mapped in the cash flow.
What other options are there to ensure that a posting record comes out in FI at the end: 40: Interest expense, 40 Tax ; 50 Treasury clearing account.