Protecting Transaction Password with OAM

Hi,

I'm integrating an online banking portal with OAM, and i'm having some difficulties protecting Transactions; what i wanted to achieve is that everytime a User

posts data to a transaction OAM asks the user to re-authenticate himself.

I've configured transactions URLs with an higher "authentication level"; obviously it is fine for the first transaction (user is re-authenticated )

but at that point the user keeps the elevated level in his session, and for any further transaction he is not challenged again.

The solution would be to get, somehow, a hook into the authorisation process and lower the session level once the transaction is complete; unfortunately OAM