Office 365 integration - extension number for new extensions?

[mowog74]

I have the O365 integration set up and it's working fine. However when I sync new users from O365, they get assigned an arbitrary extension number. Is there an attribute in the AzureAD directory where we can provide the user's extension number and have that used to create the new extension? We currently have each user's 4-digit extension in the "Office" attribute, and their 10-digit DID in the "Office phone" attribute, but neither of these seem to be included in the sync.