The default attack keys with IS Boxer, are in the FTL DPS Keymap.
They are 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, -, and =.

When you push any of these, the slaves first assist the main.
And then all windows push the same key.

Looking at these mapped keys, you could easily change both the hotkey (to activate) and the output (when activated) to numpad keys or whatever else you'd like.

Expand the Keymaps in the top pane, and left click on the Keymap.
Then in the lower left pane, click on a given mapped key.
On the right pane, you can see the hotkey for this mapped key.
Back in the left pane, if you expand Steps under the mapped key and then click on 1.
In the right pane, you can see what happens when the mapped key is activated.

The easiest would be to start your profile from scratch.
But you adapt IS Boxer hotkeys and output keys, etc, to work with any set of hotkeys you'd like.