there should be a time delay feature in the TV itself to correct the problem, you can probably find it in the TV menu (not the fios menu) and then adjust it +- 5 seconds or whatever it takes to correct the issue.
I can't find anything in my TV that will let me delay either the video or sound. The sound system has a setting that will delay the sound, but that's of no use to me since the picture is beating the sound. The problem definitely seems to be running through the TV though, because if I connect the STB right to my HT system the sound looks synced.
I guess I'll have to look into getting a splitter and running both peripherals into the HT system directly.