The simplest way of producing feedback would be to route the Amp output to the Filter 1/2 In. Start at around 50 and don't go too high. It sounds different most likely because DIVA uses a zero-delay feedback filter model with non-linear behavior.
If you ask me, that Moog style feedback sound can also be achieved just by raising the drive in Thor. Best when used with the Low Pass Ladder Filter 24 Type I, and/or 24 Type II.