ICal scripting problem

Question

Hi everyone,
I'm trying to write a brief .ics script to input my entire shift pattern into iCal and I'm making some headway although struggling with the last 5%.
I work 6 on 4 off, 2 earlies, 2 lates, 2 nights then 4 days off. No problem, I've written 6 events, each that are repeated daily with a 10 day interval.
The problem lays in the fact that the shifts that land on a Thursday, Friday or Saturday, the time of the shift changes.
Now it would be ideal if RRULE:FREQ=DAILY;BYDAY=MO,TU,WE,SU;INTERVAL=10 worked, that'd be great! Because I could just write a second event to place the events on the friday/sat/sun.
So I've sort of abandoned that idea.
So now I'm looking at placing a new event, repeating weekly, by day, and using the userID and editing a day. I.e if I set the UID of both early shifts as GPCJ-Early. Then I write an 'edit' script to run on Thurs,Fri,Sat and edit any GPCJ-Early to 07-1800 and so forth for the other shifts, that would also work.
Am I missing something glaringly obvious and a better way of achieving this? I just need to place events that repeat every 10 days, except with different times if it's a thursday, friday or saturday.
I'm testing it on phpicalendar 1.1 and I assume there must be some sort of syntax error (although it validates online) because iCal on my girlfriend's iMac says that the file is unusable. I'll cross that bridge later though!
Appreciate any help you can offer, technical documentation on iCal programming seems incredibly sparse!
Gareth

Answer 1

iCal takes its format from System Preferences>Language& Text>Formats.
Click on the 'Customize' button for 'Time' and set as here:
Then drag the  'PM' button in the 'Time Elements' section to after the short time - though when I tried this it didn't appear in iCal. You may need to experiment a bit.