How can i hook this up???

Have you tried the tape or monitor outputs from HT piece into your preamp inputs.The tape llop is usually active and the signal can be pulled from there.Good luck!

You will need to use two inputs on the AES pre, one for the two channel out from your sacd player and the other for the front L/R pre outs from your anthem. When you are watching movies you will need to set the AES pre to unity gain, try 12 O'clock. This is the same setting you will always return to on the volume nob as this is the point from which you will set overall volume from the anthem. Connect all other output from player to anthem as you have now. When you listen to music the anthem will remain off as it will be out of the picture for two channel music. The output from your AES pre will feed your amp.

Not sure if this will help but I have an AVM2. Doesn't the AVM20 have a setting called "direct" that essentially bypasses that pre and sends the signal through. Wouldn't that bypass the AVM and send the signal directly through to the AES assuming you've hooked up the AES as Tpsonic suggested?

As far as I know, the bypass on the pre/pro is not complete bypass and will degrade sound. I have a passive pre in my system I use for two channel from my sacd player and have it hooked up as I stated with the only exception of volume control setting on passive for unity gain.