Ah, sorry, I assumed you are using 2.05.
It's a bit ugly but you can use nested IF() statements to handle the localization. Something like this (remove the line-breaks that I have added for clarity):
Code:
{if(date('F') == 'January', 'januari',
if(date('F') == 'February', 'februari',
if(date('F') == 'March', 'maart',
if(date('F') == 'April', 'april',
if(date('F') == 'May', 'mei',
if(date('F') == 'June', 'juni',
if(date('F') == 'July', 'juli',
if(date('F') == 'August', 'augustus',
if(date('F') == 'September', 'september',
if(date('F') == 'October', 'oktober',
if(date('F') == 'November', 'november',
if(date('F') == 'December', 'december',
''))))))))))))}
And something similar for the previous months:
Code:
{if(date('F') == 'January', 'november',
if(date('F') == 'February', 'december',
if(date('F') == 'March', 'januari',
if(date('F') == 'April', 'februari',
if(date('F') == 'May', 'maart',
if(date('F') == 'June', 'april',
if(date('F') == 'July', 'mei',
if(date('F') == 'August', 'juni',
if(date('F') == 'September', 'juli',
if(date('F') == 'October', 'augustus',
if(date('F') == 'November', 'september',
if(date('F') == 'December', 'oktober',
''))))))))))))}