How to install the USB sub...

[mfilos]

Subway's clockport ribbon cable has a red stripe as well which based on the pic you must have it on the left side as you see it. If you check the picture correctly you will see it both on Subway and Clockport header.

[mfilos]

You can check mine to be sure:

Installed on clockport of A1200


Installed on clockport expander (same positioning of red wire)

[mfilos]

These are old pictures from my old setup mate.
It's not something difficult if you pay attention.
Just make sure you're seeing the red stripe in the left side of the clockport connector
and connect it as it shows in my pictures to Subway with red stripe facing left side close to the IC's of Subway.

Just see the pictures clearly and do exactly the same

The only think you should check is whether your Amiga 1200 motherboard has the clockport connector to the right side of the row pins (there is space for 2x Clockport connectors but only the one on the right side of the connector works. The left side connector exists in some revisions and it doesn't work!)
Check the following pics:
CORRECT connector: http://www.bboah.com/download_photos/a1200mb_rev1d4_clockport_lightgreen.jpg
WRONG connector: http://www.bboah.com/download_photos/a1200mb_rev1d4_clockport_darkgreen.jpg

[mfilos]

I dunno if simply addiing a clockport header is enough cause then it's pretty easy and straightforward moddification.
If you don't have the tools or expertise, you can contact AmigaKit if they can do that for you at a fee.

First check your motherboard.

P.S. I also made an easy diagram with the red stripe both in Motherboard and Subway. I hope it's enough
http://dl.dropbox.com/u/939939/Pics/a1200-subway.jpg