Um...
I know you know this viewer better than anyone, but you missed this one, Henri.
I use awsd all the time to move, being a mouse pointer girl myself. Just make sure the cursor isn't in a text entry field like the chat bar, and they work fine. If they're is a text entry field available, then they type a, s, d, and f, of course.
"a" and "d" turn left and right; "w" and "s" move forward and back; "A" and "D" (shifted) move left and right.
Yup, just checked. Still works on: Cool VL Viewer 1.26.15 (3) Aug 15 2015 09:57:56 (Cool VL Viewer).
Oh, and, of course, the movement floater still works fine too.