You can sucesfully record from the STB, but you need to ensure all your wiring is set correctly.
Ideally connect your TV, STB and VCR by SCART leads. One SCART goes from the STB to the TV. A second SCART goes from the STB to the VCR. Assuming your TV has two SCART sockets, a third SCART can connect the VCR to the TV.
Alternatively (but potentially a much poorer picture) connect the coaxial aerial from the STB to the VCR to the TV.
You program your VCR to record in the normal manner, timed to start stop etc, but ensuring it is tuned to the STB channel.
The biggest hassle is the STB's ability only to allow a maximum of 3 days programming using the reminder function. This is linked to the useless Electronic Program Guide. However simply set the reminder to the program you want, making sure that your user settings allow the STB to automatically change channels. Leave the STB on, not in standby, and it should switch over.
If you want more than one program, set the STB up with more than one reminder, but make sure the remnders don't overlap.
Note you can not successfully record the Front Row or similar encrypted pay per view type stuff.
If you want a program more than three days away, the only thing you can do is set a STB reminder for the appropriate channel for a program you don't want on the last available day. The STB will switch channels, and will stay on that channel until you manually alter it.
Of course it all falls over if there is a power cut
It is really a pant's system, the most annoying thing I find from ntl. When they brought out the Samsungs you'd think they could at least have allowed VCRs to change the STB channel or something. The 3 day EPG limit is I understand to alow the PACE boxes to cope.