As mentioned earlier, when you have deployed Exchange Server 2013 Cumulative Update 6 in a Hybrid deployment, several Office 365-related mailbox functions will not show up in the Exchange Admin Center (EAC). The issue was identified by Microsoft in KB2997355 and a fix was published.
However, the script to fix the issue looks for the XAML file in the default Program Files folder, using the default Exchange installation folder. Better is to check the actual Exchange installation folder, which can easily be accomplished in Exchange Management Shell using the $exinstall environment variable, or by reading the folder from the registry.
To help those installing Exchange in a non-default installation folder, and I know there are quite a few of you out there, who are hesitant to correcting the installation path in the provided FixIt script, I have create an alternative version of the Exchange2013-KB2997355-FixIt script. This version will read the installation path from the registry. Not disturbing but changed as well is correcting the XAML file in one go, unlike the official script which performs 3 consecutive read/modify/write actions on the same file.
You can download the Exchange2013-KB2997355-FixIt-v2.ps1 script here.