[AUCTeX] Active beamer.elc in LaTeX-files without \documentclass-statement

[Bernd Weiss]

Dear all,

I apologize for my ignorance but how can I activate "beamer.el/beamer.elc"
(i.e., C-c C-e should offer a "frame" option) for LaTeX-files that do not have a
"\documentclass"-statement but are included via \include or \input?

Thanks a lot for your help,

Bernd