I sent the above from my phone. If you look on the B-pillar, that guide slot is where the California blind comes down. I presume on your van, the blind comes up on the door itself. (Apologies, I don't know the Shuttle.) On the door itself, about halfway up between the doorstop and the window, you will see another seam. I reckon here is where you could have the two door styles "marry". Above this line is where I presume the blind cartridge/gubbins are on your van. I hope this helps.
Regards,
JOG