I am using the Xantech 794-10 to feed the IR input to the 990, then, I noticed that the Sherwood and Pioneer IR settings for the 794-10 interface module are the same, so I connected the IR out of the 990 to the IN of my Pioneer Elite DV-79AVi and sure enough, now both units are controlled via the rear IR. Suffice it to say that the 990 IR output works, but only with compatible devices.

Also, I originally tried to use a regular IR target/receiver, by my LCD was interfering with it, so I am getting a LCD/CFL tolerant version to try and see if it solves my issue. The first lesson I learned in trouble shooting IR, turn off other "emmitters" when doing the initial install test.