Many thanks Bob for your considerations.
Unfortunately i cannot "bite the bullet", my DSP is almost full and i have no space to fit the FIR required for HT.
I can take some benefit as my upper band is limited to 1.5KHz, so i should compensate from 20 to 1.6KHz only.
Regarding the probe/stimulus, i don't understand why they are not working with the HT block...i'll use external instruments as you did.
Bye
Tom