Dat files are the wrong format to import into after effects.
I wrote a mac app that turns dat files into time remapping data for after effects a few years ago. its called PapaAE
you can find it on my github https://github.com/RSAnimation/Papagayo
it need the rubycocoa framework so if you are running osx10.10 or 10.11 you will have to install rubycocoa to get it to run https://github.com/rubycocoa/rubycocoa
You wouldn't be able to tell me which file actually does the mapping would you.
I may be able to incorporate it in the Papagayo release I'm working on .
Or point me to a document on what remapping data is.
Thanks