[Orgmode] Bug: ical export of diary style sexps omits category and description [7.4]

[MT]

I've started using Org to export my agenda files into an iCalendar file.
I've noticed that if the timestamp is written in Org's own format, the
exported ical entry is as expected, but if the date and time is
specified in the diary sexp format, such as for anniversaries and
recurring events, some fields, such as DESCRIPTION and CATEGORIES are
left out in the corresponding ical entry. It seems that the when a sexp
is encountered, the resulting ical code is generated by the functions in
icalendar.el, without any org-related extras in defined in
org-icalendar.el added. This is not how it should be, is it? Here's an
example:

test.org:

 * Org style
<2011-02-26 Sat> An event.
* Diary style
<%%(diary-anniversary 01 01 2000)> New year

The two entries created in test.ics:
BEGIN:VEVENT
UID: TS-c7a29e46-3025-42a5-bce1-4f9712a2cd82
DTSTART;VALUE=DATE:20110226
DTEND;VALUE=DATE:20110227
SUMMARY:Org style
DESCRIPTION: <2011-02-26 Sat> An event.
CATEGORIES:test
END:VEVENT
BEGIN:VEVENT
UID:emacs19817202502127461318
DTSTART;VALUE=DATE:20000101
DTEND;VALUE=DATE:20000102
RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=01;BYMONTHDAY=01
SUMMARY:Diary style
END:VEVENT
 

-----
Emacs  : GNU Emacs 23.2.1 (i686-pc-linux-gnu, GTK+ Version 2.21.6)
 of 2010-09-01 on rhenium, modified by Debian
Package: Org-mode version 7.4

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