iI have the question in regard to the session management in the 
outsystems especially session variables between the eSpaces, am trying to fill and release session variable based on user behaviour, the variable is a simple integer value.

the problem is I can't  release or set the session variable by null especially when use redirected from eSpace to another since we can't reference the session variable between the eSpaces.


That's right you can't reference a session from espace to another, instead you can create an action in your logic and set that to public you can have getSession and setSession and reference that action to the espace you want to share the session.

I hope this will help you.