I have just found a web-site with the exploded parts diagrams for every model of the Stepwgn
The 'drilling down' is fairly straightforward, but be accurate when finding your model.
The site is <http://jp-carparts.com/honda/partlist.php?make=hond&type=STEP WGN>
Click on STEP WGN on the left side under the jp-carparts logo, and then follow the menus to find your version. keep going down until you find it. The list goes from RF1 to UF8.
When you click on the relevant model, you need to scroll down the window that opens, and you will see all the drawings you could want.
To enlarge each drawing just click on the drawing, and it opens up larger - you can print it or save it as you wish.
The enlarged drawing has the part numbers in a table below the drawing, with prices! A few pieces have no price - these may be bits that are not available through this firm, but might be available from Honda (or Bongo Fury).
Have fun exploring.