RDATE and EXDATE rules are not parsed by ical/google calendar using webcal feed or ICS file

I have an event setup that uses a repeat rule with exception dates, and a different event that uses the "additional" date field.

In the case of the first event, the repeat is included in ical (and google calendar) even when an EXDATE is provided.
In the case of the second event, the additional dates are ignored.

I've tracked this down to what I believe are lines 761 - 803 in date/date_api_ical.inc

The code produced by the template for the first event is:

BEGIN:VEVENT
UID:calendar.2815.field_datetime.2.542
SUMMARY:High School Exams
DTSTAMP:20120717T180316Z
DTSTART:20111220T131000Z
DTEND:20111220T164000Z
RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=20111222T095959Z;WKST=SU
EXDATE:20111217T000000,20111218T000000
END:VEVENT

The code produced by the template for the second event is:

BEGIN:VEVENT
UID:calendar.2818.field_datetime.13.530
SUMMARY:B
DTSTAMP:20120717T180316Z
DTSTART:20111101Z
DTEND:20111102Z
RRULE:FREQ=YEARLY;INTERVAL=1;UNTIL=20120806T075959Z;WKST=SU
RDATE:20110822T000000,20110826T000000,20110901T000000,20110908T000000,20110914T000000,20110920T000000,20110926T000000,20110930T000000,20111006T000000,20111014T000000,20111020T000000,20111026T000000,20111101T000000,20111107T000000,20111111T000000,20111117T000000,20111129T000000,20111205T000000,20111209T000000,20111215T000000,20120109T000000,20120113T000000,20120120T000000,20120120T000000,20120126T000000,20120206T000000,20120210T000000,20120216T000000,20120223T000000,20120229T000000,20120306T000000,20120312T000000,20120320T000000,20120326T000000,20120330T000000,20120413T000000,20120419T000000,20120425T000000,20120502T000000,20120508T000000,20120514T000000,20120518T000000
END:VEVENT
BEGIN:VEVENT

Google/ Ical seem to want the EXDATE in the format of:

BEGIN:VEVENT
UID:calendar.2815.field_datetime.2.542
SUMMARY:High School Exams
DTSTAMP:20120717T180316Z
DTSTART:20111220T131000Z
DTEND:20111220T164000Z
RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=20111222T095959Z;WKST=SU
EXDATE:20111217T000000
EXDATE:20111218T000000
END:VEVENT

I can't find any documentation on how/or if the RDATE property is supported.

I know this has been somewhat discussed before on some different threads, but has anyone been able to get ical/google calendar to correctly import these feeds?
Is there an official way to support these applications? Or can anyone offer any guidance? :)