Recurring iATS contributions not creating civicrm_finanical_item records
Unfortunately, the issue here is that the api for this stuff is/was a bit sketchy (Eileen's been gradually migrating and cleaning up the old IPN callback code into a better place). We've been hoping that the most recent versions of 4.7 will work and have optimistically included the code here:
https://github.com/iATSPayments/com.iatspayments.civicrm/commit/3d7db087a45024d613e2475b94e6467aa7ab873a

You're welcome to try a modification of that patch and see if your version of 4.6 creates the accounting records you want.

Failing this - I do have a lot of iATS clients that care about bookkeeping, so it's possible what you need is available, but it's beyond my understanding.