You better take a normal stock i think this will give you the opportinity to position a square on the flat:
- take a stock with the right thickness
-place a bend
-give the bend the desired radius
-give the bend th desired angle
-place a square on the stock(you need to change your tooltabel.txt if the disired square isnt there caus the custom profile is not editable on the flat)
-i have the option `create punche and forming constraints` invoked, in the options/sheet metal menu so you should have smartdimensions on your square
-change the smartdimension so that the square is on the bend
-right-click on the square in the scene-browser and use modify affected bend to get the punch in the bend
-now shorten the stock on the side that sticks over the bend to the bend
-next make the stock very small but not zero, because you need it to stick the smartdimension of the punch to hold-on to
-unfold the sheetmetal part
-click on the square in the scene-browser of the unfolded and as you can see, the square in the folded part gets coloured and if you click on it the smartdimensions in the scene get viseble and you can change them, but the change gets visible when you refold the part
Hope this helps, good luck
Wim