Hi friends

Please find the tips for creating federated resource mailbox account  for Office 365

First create user in your on premise active directory eg: “room@abc.com”

Sync this user to office 365 by using dir sync server.

then Office 365 module powershell or windows azure powershell

PS C:\Windows\system32> Connect-MsolService

Type the office 365 global account and run the below mentioned command

PS C:\Windows\system32> Set-Mailbox -Identity “room” -Type Room
Now go and check  the office 365 portal resource mailbox now you can see the federated resource mailbox there.