Here is a pic of a normal brake lever rod and pawl on the left and on the right is the fly away or
"button on" type. Excuse the rust!

The rods are basically the same but the end part is bent either up or down (as shown in the pics)
depending on what pawl is used. A normal rod can be rebent as a fly away one easily.

A close up of the two pawls. The holes in the normal one are about 20.5mm apart. In the fly away they
are about 28mm apart.

An idea came to me as I was staring at the old brake I had sitting next to my PC. The easiest way to make
a new pawl would be to grind one out of an old brake base (the bit the pawl mates to). That way you
don't need to grind the teeth since they are already there. I haven't tried this yet but it shouldn't
be hard to grind out the appropriate shape. I will need a special drill bit though to make the holes.

Click here for a bigger (177Kb) version of the above picture. You can right click and select 'save as' to take a copy.