I own a very nice (almost vintage) steel swift that has kind of a flaw with its stem riser.
It uses a 1" fork that is locked with a customized head set, that lets the fork stick out a bit on the top. This part of the fork has a slot that matches with a little nipple on the stem riser. The stem riser goes inside the fork and gets clamped by a quick-release.
(I'll post a picture of this soon)

This setup works, but is kind of unfavorable: It doesn't allow clean locking of the headset. Also the locking of the stem riser is not really ideal.

Now I plan to build a custom stem riser that looks a little like the ones made by Bike Friday.
Still I do not really get how exactly those are locked with the fork.
Can anybody owning a BF make a picture of how this works and post it here?