Doesn't read subtitles only on xbox360

I already have configured to show subtitles always in korean in my account settings. After that In every other devices I had no problem watching .smi type external subtitles. - although most clients need transcoding but that doesn’t bother me. but when it comes to xbox360, it doesn’t seem to find smi subtitles. Just says no subtitles and there’s no any options about it.

Tried to access with internet explorer in xbox360 but didn’t work out well.

Is there any solution ?