Calendar and Tasks Retention - MRM issue

I need to create a retention policy to remove items older than 90 days, with the exception of Calendar and Task items.

To prove the policy works I have a test account and set the policy to 1 Day.

Following the information in The Exchange Team Blog I've added the following to each member of the DAG:

• Path: HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeMailboxAssistants\Parameters
• Name: ELCAssistantCalendarTaskRetentionEnabled
• Type: DWORD
• Value: 0 = Do not process Calendar and Task folders

However when the MRM is run it still removes the items.

Servers in DAG are Exchange 2010 SP3 RU1

Any help would be appreciated.

Thanks

Michael Skitt