Thanks for all your feedback.
I called them and they said it's not possible.

I know the luggage storage facility in EWR, I tried it last time I had a layover there. They are some slow moving people running that, i waited for nearly 20 minutes without anyone arriving just a guy saying "wait a minute", then I got afraid they would loose my luggage, or that I would have to wait for a long time when picking up the luggage so I didn't use them finally.