As VISA et. al. begin to tighten the PCI screws, I'd like to move my authorize.net AIM payment users to SIM (and/or PayPal Standard and Google Checkout) to make it someone else's problem. This module looks useful, but I've noted that it relies on a manual action by the user (clicking on the return link on the authorize receipt page) to complete the transaction. A quick look at the SIM spec suggests that using a "relay response" post instead might avoid that problem. Has anyone looked into that yet?
Also, to repeat the question above: any reason why this hasn't been formally released on d.o? Anyone already working on that?