Solved.
The vast majority of this is PowerShell script. (Start > Powershell Modules)
First of all you need to set up the web proxy: (to be honest, I skipped this bit as the iPad in question will never leave the building and an external URL isn't required)
To check settings:
Get-ExchangeServer |fl
To set setting:
Set-ExchangeServer -Identity "MAIL01" -InternetWebProxy "<Webproxy URL>"
Next, the virtual calendar directory needs to be set to shared:
To check settings:
get-owavirtualdirectory |fl
To set setting:
Set-OwaVirtualDirectory -Identity "CAS01" -ExternalUrl "<URL for the CAS01>" -CalendarPublishingEnabled $true
Next, in the Exchange Management Console, go into Organisation Configuration > Mailbox and create a new policy. Set the domain to Anonymous
(this is the bit that threw me as I assumed using the * wildcard for domain would do what I was after but no!) and the sharing settings to Calendar sharing with free/busy information
and whatever level of access you want to give people.
Assign the new policy to the resource mailbox:
Set-Mailbox -Identity <mailbox alias> -SharingPolicy "<sharing policy>"
Enable publishing on the calendar:
Set-MailboxCalendarFolder -Identity <mailbox alias>:\Calendar -detaillevel fulldetails -publishenabled $true -reseturl
At this point you can see the mailbox's url (both as an html to view and an ics to subscribe to) by running:
get-mailboxcalendarfolder -Identity <mailbox alias>:\calendar
At this point, I believe it's sorted. As an added extra though I figured out how to send an email from the calendar account. First log into OWA as you would normally (note, your account needs to have a level of control of the room account. I had mine set to full control and send as), then change the url to https://<OWA url>/owa/<full email address of room>/#
Apologies for any lack of detail or terminology. Hope it all makes sense.
If you have delegate access to the calendar, does that mean that the room calendar items display in your calendar? – Miles Hayler – 2012-12-17T08:51:55.587
Yes. – bb010g – 2012-12-17T13:48:58.583
Being the delegate still requires opening the other calendar. Per the link you posted: link
– Miles Hayler – 2012-12-17T14:52:01.263Is it not able to be enabled on the iPad? – bb010g – 2012-12-18T04:21:55.590
1I cannot add the calendar, regardless of whether the account is a delegate or not. – Miles Hayler – 2012-12-18T10:33:16.157