My experience with the Sperry Helipilot system on Bell 412's and S-76's demonstrated the aircraft could get you down to 50 feet AGL using the RadAlt and the system tracking the Localizer and Glide Slope....and do so at 60 Knots IAS.
Unfortunately, the A109S autopilot isn't quite so sophisticated as that in the S-76.
The AP has no facility to carry out an ILS with the aircraft holding a set airspeed (the collective isn't coupled and there is no altitude pre-select facility). During the ILS the airspeed is controlled by the pilot using the collective and it can be counter-intuitive until you are used to it; it will easily go through Vne or VLE (max landing gear extended speed) as it couples to the G/S and noses down - it's a slippery beast and can get away from you. At lower IASs, with the AP fully coupled, the aircraft seems to "wallow" as if the AP is struggling - it's designed to fly fast.
The AP is capable of leveling the aircraft at the completion of the ILS but at that stage the airspeed still has to be controlled by the pilot using the collective. It's actually quite unnatural to significantly lower the lever - lowering the lever brings up the nose, rather than the possibly more usual expectation of it causing the nose to drop. If you are still in fog at that stage and not used to it, possibly more than a little disorientating.