Problem with mapping mailPrimaryAddress to targetAddress

Hi folks
I am currently trying to implement a custom mapping that syncs ‘mailPrimaryAddress’ to the attribute ‘targetAddress’ in AD.

To accomplish that i tried to use the file at ‘/etc/univention/connector/ad/’.
Now, I’ve got it to sync but i need the specific prefix ‘smtp:’ in that targetAddress attribute.
How do i accomplish that?

Best regards

Only guessing, but Univention is doing some mangling in as part of the UCS AD Connector, maybe you can take some inspiration from that?