I just thought about it and this will probably not work when controlling the PLC because the Alt-B action clicks the button, but the PLC writing is activated by Mouse Down and Mouse Up events.
Another option that may work is to Tab through the controls to get the button highlighted that you want to click , then press Enter.
Or you could write to the PLC via code in the Click event handler. In the example above, instead of using the MsgBox, you would use something like this:
EthernetIPforCLXCom1.Write("MyButtonTag","1")