I am in Panama right now, so I don't have access to all the good stuff.
I can't even access deltamotion.com. Weird.
When hydroforming you are doing the water or oil-based equivalent of blow molding plastics.
Anyway, Delta has experience at doing several different kinds of hydro forming going back to the 1990s.
It is possible when one uses an intensifier where the pump pushes on a relatively large piston. It rod is connected to smaller diameter cylinder and piston. The forces on the two pistons will be the same but the smaller system will be able to increase the pressure by the ratio of the surfaces areas.
To be stopped the load and applied must be equal but there is a difference between a mass type resistance and what happens when you try to pressurize a volume.
Visit our website and look for applications.
deltamotion.com
I will be back and be better able to answer questions.