Problem with CST timezone

Hello,

I am using my iPhone, iOS 6.1, connected by CalDAV with an own application. The problem I am facing is that when receiveing an event in CST (Central Standard Timezone) the hour it is not the correct. I am in Europe/Madrid, so the event should be shown six hours later.

Any idea if there is an issue with this timezone.

Thanks in advance

PS: this is the ics content of the event:

BEGIN:VCALENDAR

PRODID:-//OWNID//XXXX//ES

VERSION:2.0

METHOD:PUBLISH

BEGIN:VEVENT

LAST-MODIFIED:20130207T080609Z

DTSTAMP:20130207T080609Z

UID:040000008200E00074C5B7101A82E00800000000B0A366859000CE010000000000000

000100000001AE05AA6C2185B4AA39CC59F0B49161E

SUMMARY:This is the summary

PRIORITY:5

DESCRIPTION;LANGUAGE=en-US:Meeting information

CLASS:PUBLIC

TRANSP:OPAQUE

SEQUENCE:5

LOCATION;LANGUAGE=en-US:videoconference

X-MICROSOFT-CDO-APPT-SEQUENCE:5

X-MICROSOFT-CDO-OWNERAPPTID:-1564399651

X-MICROSOFT-CDO-BUSYSTATUS:TENTATIVE

X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY

X-MICROSOFT-CDO-ALLDAYEVENT:FALSE

X-MICROSOFT-CDO-IMPORTANCE:1

X-MICROSOFT-CDO-INSTTYPE:0

X-MOZ-RECEIVED-SEQUENCE:5

X-MOZ-RECEIVED-DTSTAMP:20130206T172337Z

X-MOZ-GENERATION:1

DTSTART;TZID=Central Standard Time:20130212T090000

DTEND;TZID=Central Standard Time:20130212T093000

STATUS:ACCEPTED

CATEGORIES:

BEGIN:VALARM

ACTION:DISPLAY

TRIGGER;VALUE=DURATION:-PT15M

DESCRIPTION:Descripción por defecto de Mozilla

END:VALARM

END:VEVENT

BEGIN:VTIMEZONE

TZID:Central Standard Time

BEGIN:STANDARD

DTSTART:16010101T020000

TZOFFSETFROM:-0500

TZOFFSETTO:-0600

RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU

END:STANDARD

BEGIN:DAYLIGHT

DTSTART:16010101T020000

TZOFFSETFROM:-0600

TZOFFSETTO:-0500

RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU

END:DAYLIGHT

END:VTIMEZONE

END:VCALENDAR