I have defined macro for "Open Document" event that is normally
executed if I open same .odt document in OpenOffice writer.
Is there some extra setting that allows macros to be started?
To enable them you need to set the "MacroExecutionMode" property
http://api.openoffice.org/docs/common/ref/com/sun/star/document/MediaDescriptor.html
http://api.openoffice.org/docs/common/ref/com/sun/star/document/MacroExecMode.html
How to do that depends on which JODConverter version you're using and
how you're using it.
Kind regards
Mirko