I think you've tried 2 of the ones that you should have had a decent chance of keeping alive... Dunno what else to tell you.
My strategy is to let the expert aquarists in my area keep the anemone for the first few years, then swoop in when I smell a sale...
Just kidding, but I haven't bought one new. The LTA i now have was with EmilyB for what, 4 years? I think it was well acclimated to captivity by then...
Don't ask the guys at wetwebmedia, they'll tell you anemones shouldn't be kept at all (case in point).