I needed to setup my Harmony remote to be able to control both the TiVo Series3 and the DIRECTV HD DVR. I thought that there was a setting in in the Harmony interface, but I couldn't find it. Here is the way that I was able to get this to work:
- Configure the remotes and TiVo for seperate remote addresses.
- In the Harmony remote application, click on the Settings for one of the TiVos.
- Select the "Confirm infrared commands" option.
- Follow the instructructions.
- Do the same for the other.