[Zope] persistent sessions with ZEO not working

I'm maintaining a ZEO cluster setup that currently consists of 2 Zope clients and 1 ZEO server (Zope version is 2.10.5.) I'm using sessions on the hosted site and am having trouble sharing them across the 2 servers. I've done a config as described here: http://www.zopelabs.com/cookbook/1061234337 Everything runs fine, except my sessions 'change' randomly. For example if I output my SESSION data I notice that the sessions ID is not persistent over i.e. 10 page loads. The contents of the sessions also change, of course. Am I missing something here? The central storage of the sessions should fix this if i'm correct, but it doesn't. Is this impossible to do, or is another issue causing this stange behaviour? best regards, Marko