Error when posting to satellite server

Hi,

I try to post a web form to a satellite server. For rendering the form I use the <satellite:tag> as suggested. As long as I use method="get" is works just fine. When I switch to post, which I need to use as we offer file uploads in the form, the first post works. The second one could not be processed by Content Server. The page which renders the <satellite:tag> is cached. The page which processes the post is not cached.

In sites log of Sites I just get an Error "Bad request". In the Satellite log however it states "Bad parameter". So my thought is that, as the first post works, that the _authkey_ might be the problem as it is cached.