Seam 2 with conversation and Internet Explorer doesn't work

Question

I have a strange problem in my application with Seam (2.1) and Internet explorer.

With Firefox, all work fine. I have a bean in conversation scope which is used in my page. When I go on my page, this bean is created, and when I made an action on my page (submit a form for example), the bean already exists and all these data are present.

But in Internet explorer (7 and 8), the bean is created at each call of the page. So I lost every data in this bean.

Someone can help me ?

Thanks.