Asp.Net : IHttpModule + m_context.Server.Transfer = session state error

I have an IHttpModule that implements IRequiresSessionState.

The session state is at "on" on the page directive and I also added it to the web.config. In the method "OnBeginRequest" in the IHttpModule, I make a S开发者_C百科erver.Transfer but I get the error :

Session state can only be used when enableSessionState is set to true, either in a configuration file or in the Page directive.

When I access the page directly or with a Response.Redirect, there is no error.

Any idea?

Update :

The error occur in a page extending System.Web.UI.Page in the method InitializeCulture() which is an override.

Well, since I'm using DashCommerce, I used the Rewrite URL module instead and it worked fine.