It appears you heard right. You can do both, just not at the same time, but you can't use the Video Sender to forward the TV2 remote control commands since it is RF.
From the manual:
Dual Mode
While in Dual Mode, you can use this dual-tuner satellite receiver to watch different programming
in two separate locations:
• Nearby TV—Programming from the receiver is delivered to the TV near the receiver using
short audio/video cables and is controlled using Remote Control 1. The nearby TV is also
referred to as “TV1.”
• Remote TV—Programming from the receiver is delivered to a TV located in another room
using existing in-home coaxial cable and is controlled using Remote Control 2. The video
displayed on the remote TV is always in standard definition (SD). High-definition stellite
Single Mode
Single Mode provides dual-tuner receiver features—like Picture-in-Picture (PIP) and the ability to
watch one live program while recording another—to all connected TVs.