Hi Claudio
I am not sure if your approach for General Valuation Class and the valuation classes is correct especially if you only have one GAAP.
First of all the distinction between Trading, AFS and HTM only makes sense for Bonds. The reason for this is the amortizing cost over lifetime. Therefore you cannot use these groupings for money market, shares etc. For FX deals and Derivatives it does not makes sense to use any of those as they are not recoreded on the balance sheet.
For the split of money market into short, medium and long term I would rather use the transaction types e.g. 200 for short term, 201 for medium term and 202 for long term. Also this split only makes sense if you have to post to different balance sheet accounts e.g. 200111 for short term, 200222 for medium term etc. If this is the setup at the end of the month you can change the account assignment reference with transaction TPM28.
Regards
Juerg Heiz