Corba: JPEG export

Hallo,
i control the InDesignServer over Corba and communicate with java.
I can export a PageItem as JPG but the resolution information is always on 72 ppi.
Although I set these informations. application.getJPEGExportPreferences().setJPEGQuality(kJPEGOptionsQualityMaximum.value);
application.getJPEGExportPreferences().setJPEGRenderingStyle(kJPEGOptionsFormatBaselineEnc oding.value);
application.getJPEGExportPreferences().setResolution(2000);

pageItem.doExport(VariableTypeUtils.createString("JPEG"), jpg.getAbsolutePath(), OptArg.noPDFExportPreset(), OptArg.noString(), OptArg.noBoolean());
Thanks for Help!