Form State Keeper solves the problem of form posts being lost when authentication tickets expire.
It is a simple HttpModule for ASP.NET. The HttpModule will capture the posted form and save it using a provider model, just before the forms authentication redirects the user to the login page.
After login, the same HttpModule will redirect the request to a custom http handler that generates a transit page. This transit page will restore the form contents as hidden fields and do a submit (http post triggered on load) to the original page. There you go, form restored.
These details are provided for information only. No information here is legal advice and should not be used as such.