planner appointments exported to icalendar events

Hi,

after managing to keep all my personal information in Emacs (hooray to
planner, muse, gnus, and bbdb!), I came to the conclusion that the outside
world still uses other tools, and they often ask me for some portions of
information. One of such is my schedule. So I promised to give them an
iCalendar .ics file, and dug into Emacs to code some elisp to make it
work. First, I found icalendar.el, and then planner-ical. Both wouldn't work
for me:
1)  icalendar.el provides a simple API, directed to diary<->icalendar
    migration. It doesn't merge information :(
2) planner-ical.el is a work in progress, I suppose. It only converts tasks
   into VTODO, and only from one page at a time.

So I thought about what I needed:
o export all my future appointments into VEVENTs. This includes cyclic events,
  and tasks with time informations (both handled with planner-appt).
o import a full icalendar into planner. deal with VEVENT, VTODO, VJOURNAL, and
  create, respectively, schedule entries, tasks and notes. add the appointments
  retrieved from the VALARMS.

The code I made today fulfills, although not wonderfully, my first
requirement. I'm using it specially to communicate my availability to my
co-workers. So I added a regexp argument to filter each entry by its planner
category! The only thing I can't seem to manage is to get planner-appt to tell
me the category of a task-appointment. So right now I export all of the tasks!
Anyone knows how I can get this behavior?

Here's the code to export to a ics file: