we have a fresh Windows Domain (Win2k12) and installed AAD Connect (latest version) and established the sync to an Office 365 tenant with default settings.
Now, after the syncrhonization ist working fine, I installed the Exchange2013 schema extension in the AD.
I did this, because I want the possbility to edit some AD-Attributes, that are not available in the cloud (msExchHideFromAddressList) with AdsiEdit. (I know it is not supported).
After the schema extension I did a "Refresh Directory Schema" in Azure AAD Connect.
After that the new attribute "msExchHideFromAddressList" was still not synching to the cloud.
I found out, that I have to do following:
"Synchronization Rule Editor":
Rule: "In from AD - User Common"
There I added a transformation that maps the attribute.
OK, this is working now.
But how do I know which Exchange-Attributes would bei used in the future?
Which attributes do I have to map?
Or is there a possibility the map the needed attributes automatically?
Many thanks in advance!