Set maximum number of days in resource calendar to 365days

To do this, You will need to open the resource mailbox via owa 2007
 
Note:To use this features, you must be granted FULL ACCESS to another user's mailbox or resource mailbox that you want
to open
To open the resource mailbox:
1. Please login to OWA
2. Click on your name in the upper right corner of the window:
3. In the “Open Other Mailbox” dialog box, please enter the name or email address of the mailbox that you want to open:
4. If more than one matching entry is found, Outlook Web Access will list them all.
5. Choose the mailbox to open. The mailbox will open in a new window.
6. Click on Options on the upper right hand corner next to the mailbox name
7. Click on resource settings on the left
8. On the right, type 365 for the maximum number of days:
9. Click on Save
10. You 're done
Troubleshooting
If the mailbox doesn’t open and you get the following error message instead:
"You do not have permission to open this mailbox. Contact technical support for your organization for access or for more information.",
then you need to make sure that you were granted FULL ACCESS to that mailbox.