SSL/TLS: Certificate chain challenges

Update #1: I've updated the part "Get them into our webserver" by adding a link back to the first SSL/TLS Post where i describe how to correctly create the bundle files! In my last post i've described what you need to do with the new site and intermediate certificates…

SSL/TLS: How do i get HTTPS for my site with a valid certificate?

For me using SSL/TLS for websites or connections between servers and clients in general - think of PostgreSQL connections or OpenLDAP - is no rocket science and my daily business. But in the last months i read a lot of tweets and articles about that topic and talked to…