I just updated my firmware this afternoon and this is a pretty cool feature. I have a sample size of one entire movie but it worked for that one.
I tried terminator salvation on my ps3 and it had the subs half in the picture and half in the black bars, there for projecting onto my wall. I then put it in the Oppo, held the subtitle button, pushed the up button a couple of times and presto! Subs in the picture. This was on the blu ray version.