Document Classes ⇒ Beamer - Footline disappears with \setbeamertemplate

[AlexS1985]

Hi guys,

I define my own class, and again I have a problem, which is more a question for my understanding.

You find my attached files, a minimal class 'class.cls' and a tex-file 'class_test.tex' that uses my self-defined class.

In class.cls I define a footline with the command \defbeamertemplate*{footline}{bla}, that is immediately active, because of *. Ok, I'm fine, everything looks good. Now I remove the *, and invoke the footline in class_test.tex AFTER \begin{document} via \setbeamertemplate{footline}[bla]. What happens is that the footline almost disappears under the lower margin.
Now I invoke the footline in class_test.tex BEFORE \begin{document} via \setbeamertemplate{footline}[bla] and everything is fine again.

My question: What is wrong within the environment 'document'.
I mean, I also define \defbeamertemplate{frametitle}{blubb} and invoke them AFTER \begin{document} via \setbeamertemplate{frametitle}[blubb] and it works and looks the way I expect it.

I hope anyone is able to help me.

Thanks in advance. Best wishes,
Alex

P.S. I posted this topic also on mrunix.de
http://www.mrunix.de/forums/showthread.php?t=70920