I am able to capture click data when attempting to serve up Target content in emails deployed via Campaign Classic; however, when I run tests focused on impressions for the Target content, nothing comes back via A4T.
Normally there's a metric called 'activity impressions' in Analytics that is populated via target and their impression data (in the A4T use case). I presume you looked there. If that is 0 or isn't populated. Then Target itself isn't capturing impressions. I'm not sure how well things like target work in the scope of inside an email, and what email clients allow to be executed inside of them. I'm not sure if any of this helps though.