There is a flip cover at the main pivot point on the wiper arm. Flip the cover open and remove the thin flange nut. I can't remember what metric size it is. Now it seems very difficult to remove the wiper arm but it is not. This arm is on a spline so you need to first flip the wiper blade off of the window to get the pressure off the assembly now just a bit of a wiggle and it should come right off. Remember the wiper arm pushing against the glass puts side pressure on the spline so this is what keeps it engaged/locked on to the assembly. The seals were just fine on my 2000 all Minnesota car. You can get details also from the download manual go here:
Download 2000-2006 Insight Service Manual PDF and Others. Use the "wiper_washer.pdf" file from the "Honda-Insight-2000-2006.exe" file. The .exe file will ask you to select a destination to save/extract the files to. Sounds like you already know how to remove the inside panel and access the back of the hatch it is just getting the wiper assembly off. If this does not help let me know and I can shoot a quick vid and e-mail you off-line. FYI one of my three nuts that holds the wiper motor in place was stripped so I used a heavy duty cut-off wheel on my dremel to cut the top of the nut off but keep the threads in tack for support. Working just fine being locked in place by the remaining two nut/bolt assemblies.
