Use extensionAttributes for filtering users in MIM 2016

Hi, 

i set up a new installation of MIM 2016 for User Profile Sync with SharePoint 2016.
The customer wants to filter out active directory users which have a value in "extensionAttribute10".

I tried to create a new connector filter, but i don't find these extensionAttributes to filter:

Maybe because it's an Exchange Attribute? Is there another possibility?

Best regards,