HowTo? Localization of local customizations of RT3

I have done some local customizations of RT3.0.2, that consist of

A) code patches and enhancements via lib/RT/*_Local
B) Mason Overlay of dyamic pages via local/html
C) enhancements via the Callback mechanism local/html/Callbacks

I would like to make my enhancement at most bi-language (english, german),
but I do not know the mechanism to provide localizations for enhancements.

Is there one? How do I use it?

Thanks,
Dirk.

Dr. Dirk Pape (Leiter des Rechnerbetriebs)
FB Mathematik und Informatik der FU-Berlin
Takustr. 9, 14195 Berlin
Tel. +49 (30) 838 75143, Fax. +49 (30) 838 75190