you do not have the hardware to hold the knee lever. there are two types, and one is part of the handle, the other is a couple of clips on the side.
It looks like the handle pulled out at one point and was repaired. It's very possible the original handle with the holder for the knee lever was damages or lost, and it was replaced by the much more common style without it.
It is also very possible that this lid did not originally go with that machine.