You can use /play/pbm/showpiece.php?set=motifshogi&piece= and /play/pbm/showpiece.php?set=alfjapanese&piece= with the labels used in Game Courier sets for Shogi as the piece names.
Showpiece.php-generated pieces are not useable in the Interactive Diagram, as they distinguish the armies by case rather than prefix. The underlying files offer a better bet, as there the armies are distinguished by an extra 'Flip' suffix in the filename, and by defining them all as 'extraneous pieces' in the I.D. we can indicate where in the pathname of the file the 'color-prefix' should go. And then define blackPrefix=Flip and whitePrefix the empty string.
[Edit] I now set it up so that the non-believers can try it. Because of the incompatible piece names I had to make different applets for Motif tiles and Alfaerie, and to prevent you can see the piece flip when a slightly altered position in the same representation is shown, it now sets up a new random position of 40 randomly chosen sente pieces on a 9x9 board, and then changes one of those to gote.
Showpiece.php-generated pieces are not useable in the Interactive Diagram, as they distinguish the armies by case rather than prefix. The underlying files offer a better bet, as there the armies are distinguished by an extra 'Flip' suffix in the filename, and by defining them all as 'extraneous pieces' in the I.D. we can indicate where in the pathname of the file the 'color-prefix' should go. And then define blackPrefix=Flip and whitePrefix the empty string.
[Edit] I now set it up so that the non-believers can try it. Because of the incompatible piece names I had to make different applets for Motif tiles and Alfaerie, and to prevent you can see the piece flip when a slightly altered position in the same representation is shown, it now sets up a new random position of 40 randomly chosen sente pieces on a 9x9 board, and then changes one of those to gote.
You find the applets here: Alfaerie Motif Tiles