It is setup right on the modem (the Draytek is checked to bridging mode, the isp field is blank, it's set to PPPoA):

Here's the Tomato page with RAF:

And, correct me if I'm wrong, in theory it shouldn't even matter what is set in the User/Pass fields even, right? Because I know I can (accidentally) put the default Xtra broadband user details and it works - I have even put admin/admin as the user/pass in a modem and it still did a complete PPP handshake etc.
I have done this successfully with a Cisco RV042G (works perfectly, every single time), I have even got it working with a Tenda W1800R using the stock firmware.
Why? Because it is just works! It's not a complicated thing, it's supposed to be straightforward.
And yet, I can't get it to work. For the life of me, it just will not work.
Can anyone help me? At some point I want to try playing with a RB750 Routerboard to do the same, but I think right now I should stick with trying to figure this out.
Please let me know if people want more screenshots of my configuration/settings.
Thanks for your help!
P.S. This is not for a job, thankfully, this is just for home.