In order to perform this type of recording, you will need to install DVBViewer and the Dabdig scripts.
The first step consist in selecting the capture device to monitor. To do that, use the drop down box and press the "Associate" button, the capture device will be shown at the bottom. Only one device can be monitored, though this might eventually change. Next, you need to enter the full path to the Dabdig scripts. Finally, enable the "Auto execute" and you are set! Well ok not quite, this is still untested and will most likely require a table of channels to link Beyond TV's channels to the ones used by DVBViewer... So, any guinea pig?