I don't have enough room for a proper press brake, and it seems that a shop press brake adapter for my shop press isn't available in New Zealand, but what I have found, is a good way to break your vice. The Vice Brake is sold as being capable of bending 2mm mild steel, and while this might be true for small pieces, you vice will struggle to do a long bend in 2mm.
Enter the vice brake shop press. This works surprisingly well, with the vice brake seemingly very stable and not at all threatening to explode out the side.
Of course, even a small 10 tonne shop press is much more powerful than a vice. I used the back, less visible, end of the die to bend a small piece of steel and didn't supervice it sufficiently. This damaged the die, but it still copes with bending 3mm steel.