From an intellectual property standpoint, I believe it is reasonable to assume the two are completely unconnected until evidence can be shown otherwise. I'm not aware of any evidence that the Wyss Institute of Harvard has contributed anything they have learned or gained in their DARPA contract to assist or collaborate with ReWalk.
In fact, it is quite possible the Wyss Institute's DARPA agreement explicitly does not allow them to talk about, let alone use the technology they are developing for the D.O.D. in consumer products, like those they are working on with ReWalk.
If you look into the terms of government contracts you will find that the government has most of the authority and control over whether or not the party they contract can use a patent they are granted while working on their government contract, for commercial purposes. However, generally it is the government's goal to allow the companies to do so. See:
Here's why the opposite might be true: Ekso Bionics having more overlap with Wyss than ReWalk. I'm certainly not a patent lawyer, but I do read a lot of the exoskeleton patents and watch a lot of what DARPA publishes.
Watch this video. The main speaker is the project manager of DARPA's Warrior Web program:
It appears to me he is wearing cables and pulleys while demonstrating with the soft exoskeleton he says is made by the Wyss Institute (notice what looks like cable contractions at his stomach while he is walking around down the aisle). It's unclear how old the technology is that he is demonstrating. (I believe he meant to say the force being placed at the foot is the worst place to put it, not the mass. My believing this is based on the fact he's showing a force diagram not a mass diagram)
That being said, now look at Ekso Bionic's & ReWalk Robotic's patents:
both of these patent applications speak about pulleys.
Also, note that Ekso Bionics has stated this:
"This is the fourth time DARPA has tapped the company’s Ekso Labs™ division for its unparalleled exoskeleton knowledge to develop a more advanced generation of exoskeletons."
News 
Market Data 
Discover 
