Hook the button to an empty handler or set button to send keep-alive message rather than an emplty SysEx.
You did not mention what tools you use to create your program, but if you develop your own program you could connect the button to a handler that does nothing, or not connect it to any handler at all.
If you are using some development kit that creates the program 'automagically' you might have to set it to some MIDI message, and if so, I suggest you use the keep-alive message instead.
Br, Hobbe