Okay,
Etherian Space Program here's a quick tutorial on how to make shuttle doors on SFS.
First of all, I told you . I assumed you knew what "secure a fairing is". My mistake, sorry. This is what secure a fairing is.
(IGNORE THE FLAT TEXTURES).
View attachment 28308
I think this image is self-explainable. Those structs are securing the fairing. That's what I was referring to.
Now, on a shuttle you usually secure both fairings, but not like the example above. Here's the cargo door I've designed for your shuttle.
View attachment 28309
See? I'm securing the right fairing to the body of the shuttle, while the left one, although secured to the probe, is free to move. So, how to open it.
View attachment 28311
You need to touch the docking port attached to the capsule, the 4-wide separator and the bottom docking port, that will open the door. Now, all you have to do is to dock the door somewhere, and the door will be opened!
To close it, simply move the shuttle with RCS and dock the 2-wide docking port on the right side of the probe, to the 4-wide docking port on the shuttle itself.
View attachment 28313
I hope you see it more clear now
Now this method works, not only with your shuttle, but with any shuttle and payload door you are going to design. Now, on this post I'm attaching the fixed bp of the vessel AND a quicksave file with the shuttle already in orbit, so you can try the door. Download TtTOtW's Archie shuttle too, so you can have another version.