There is no HDMI or data signal when the tablet is connected to the Cradle, and the Cradle is connected to the HDMI Adapter Cable or the USB Adapter Plug.
The HDMI® Adapter Cable (SGPHC1) and USB Adapter Plug (SGPUC3) (both sold separately) will not function when connected to the multi port on the Cradle (SGPDS2).
This is as designed and is not a defect or service issue. The HDMI® Adapter Cable and USB Adapter Plug will only function when connected directly to the multi port on the Tablet. This is because the Cradle does not have the ability to pass through either an HDMI or USB data signal.
NOTE: This information is specified in the User Guide for the Cradle.