I've used the rear IR inputs of two different Onkyo receivers, and they worked fine without having to strip out the carrier. Now one thing to check is that the Onkyo receivers have two input jacks, one labeled IR IN and the other RI (remote control). You want to plug into the IR IN. The RI input is a proprietary Onkyo interface.

Now that may be your problem on the DVD and Tuner devices, since the ones I've used only had RI inputs. To control the DVD and Tuner using these rear jacks, connect the receiver's RI jack to the DVD and Tuner RI jacks. The DVD and Tuner should have two jacks to allow for a daisy chain. Also, for RI to work you must have analog audio cables hooked up the receiver, even if you are using digital. Then, you send the DVD and Tuner commands "through" the receiver using the receivers code set for those devices.

Anyway, I hope this helps some.

Dino