[koenfucius]

What I have found since posting the original query is that sometimes the V+box "forgets" about the padding. I guess this happens as a result of a poorly constructed software update. What has worked for me then is a combination of reprogramming the padding (in my case, I pad 2 minutes before and 5 minutes after), and then deleting and reinstating any 'series' (because I have also found that the padding only applies to new recordings - any recordings that already exist are not affected by changes to the padding). Hope this helps!