Maybe, a better fix is to change the date format, i.e. xx. März to xx.03.
I found only two occurences of the long date format (month as name). The posting time in the entry and thread views of postings and in the bookmark listing table. Every other place seems to use the short date format with the month as a number with leading zero. I never saw the question to extend the use of the month names instead the numbers from anybody using any of the supported languages. So I assume, to "kill" the last two occurences of month names would not harm anybody.
So, long story short, I support your proposal.
PS: Leave the key in the language file. Maybe it's useful in other cases.
Trenne niemals Müll, denn er hat nur eine Silbe!