I got a full registered DVDA Studio 4.5 at home but I'm currently away from home :(
is it possible to design a DVD with the trial version (menus, chapter markers, etc) and then, once back at home, open the .dar file and burn the resulting DVD ?
Can't say with absolute certainty, but my best guess is that this would work, assuming that the .dar file can be saved, and you're using the same (or later) version of DVDA Studio.