I am not familiar with your module and might not be understanding this right, but the logic suggests that if your Wall-Button is a physical button and brings the voltage to the input of the module when it's switched ON, then you cannot really control that input through the logic by using AHMI (the switch that you mentioned shouldn't have effect when you click it).
Can you provide more information about your setup, what switches and indicators are doing in the AHMI and what will Wall-Buttons be doing as well?
If your module only allows you to read from the inputs and write to the outputs then you can use VB code to setup a logic that compares the states of physical and logical inputs and then writes to the outputs.
Most of this stuff is normally done in the ladder logic and physical devices cannot be controlled by software.
Who knows, Archie might have a better answer/suggestion about this.