Keyboard navigation triggers next rather than action button

This is something we intended to look at as part of our project but we've run out of time / budget - so I'm raising it, in case anyone else is able to.

I've set up a number of tour steps, most of which have Back and Next buttons but for some steps I've replaced the 'Next' button with a custom action (mostly basic stuff - e.g. click a menu link and then call next).

This works fine when navigating the tour using the mouse but, if you use the keyboard navigation - the right arrow key will always just move the user to the next tour step and never trigger the custom action.

Could there be a way to specify which button should be triggered by the left and right arrow keys? Or, as a bit of a fudge, could the right arrow key trigger the first button on that step which has an action with a class of 'next-button' (and vice versa for the back button)?