The inventory that you get when using the new graphics isn't affected by what you do while playing with the classic graphics.

So you can make the dynamite the current item in the new graphics inventory, switch to the classic graphics, use the shovel with the X, and then switch back to the new graphics. When you open the inventory after the cutscene, the dynamite will still be the current item and using it will be very easy.

Disclaimer: I don't know whether this technique saves time over simply using the classic graphics during the whole sequence.