Always trying to fix something that's not broken, raises a question.
If I import a mp3 with meta data in it into after effects, and I edit the marker's comment, does this actually change the text that will be saved in the F4v file? the problem I have is that XMP seems to only work with english and we'd like a searchable video in Russian.
XMP is full Unicode (like any XML flavor is required), so there are no language problems per se. Actual searchability therefore would just depend on the host app providing access to it based on the language settings, i.e. you will probably have to work on a Russian system to see proper results...