Function DateFormat and Reports_Locale

[picht]

We use this expressin in a text field:

IF($P{P_JAHR}.equals( "NO" ),DATEFORMAT($F{MY_DATE},"MMMM yyyy"),
DATEFORMAT($F{MY_DATE},"yyyy"))
 

it means: Depending of the parameter p_year (YES/NO) it prints the date as 2015 or March 2015.

The user can decide, in which language the output shal be generated.

But the REPORT_LOCALE has no effect on this expression.

I think, DateFormat.getDateInstance(DateFormat.LONG, $P{REPORT_LOCALE}).format( $F{MyDateField} )

will not work, because I need exact the format above not something like March 1, 2015.

Thanks in advance.

Carsten