I'm, not sure why you need binding. You could "hide" the panel just by excluding some object from the collection. So during re-render panel for this object will disappears.
Session scoped bindings b.t.w. is not good design for JSF in general - and I guess you using it.
I need binding becouse of need of manipulate objects with calling methods in backing beans. In order to do that I must have object instance. I can't set id dynamically in jsf 1.2 so I can't obtain object instance through id, couse when components are creating at runtime I don't know id generated by JSF.
So, when I can't know id the only way is create dynamically objects and binding them on the page.
actually you could define id's with EL if using facelets.
I use facelets. Can You tell me how can I do taht pleas?
a4j:repeat doesn't create separate instances of panels, so you will be binding always the same panel, please take a look: http://www.ilikespam.com/blog/c:foreach-vs-ui:repeat-in-facelets
"binding" usage is not a good way to modify components' properties, the better way is to wire necessary attributes to repeat iteration variable properties via EL-expressions.