The only major problem with editing a PvE build for PvP is that Warlocks in PvP are a survivability class, as SL/SL and an occasional heal we out-live the opponent. in PvE we are a damage dealer that should not be taking dmg thus not needing the core-pvp talents in a raid. Soul link, siphon life, demonic resilience are some that come to mind, of course an affliction warlock might take siphon life to lessen the burden of life taps. And you might take demonic resilience if you plan to group as felguard spec, but I dont recommend it until you do a lot of pre-heroic instances so you can learn when to pull him out of danger and when its safe to send him back in. I would work on a strong affliction/sub-demo build till you can get the hit rating and crit for destro.