[Plugin: WordPress Navigation List Plugin NAVT] Problems when $sBefore and $sAfter empty

Hi

I don’t want NAVT plugin to apply <ul> before my menu
so here is my request, and it works:
navt_getlist('groupes', true, '','','');

the only problem is that two <> appears in my page, and I don’t know where they are coming from

Thanks

WordPress Version 2.8.4
NAVT v1.0.34
https://www.ads-software.com/extend/plugins/wordpress-navigation-list-plugin-navt/