Thais (hope I spelled your name right...),
Actually I used MuseScore with the "GeneralUser GS.sf2" Soundfont from (http://www.schristiancollins.com/generaluser.php) and saved the file as a ".FLAC".
From there, I used the free online audio converter site (http://www.online-convert.com) to convert the ".FLAC" to ".MP3" although there are many other ways to do this.
Next I Used "Windows Movie Maker" (although "Windows Live Movie Maker" works as well) to add title and credits to the audio portion and save as a ".WMV" file.
Lastly, I uploaded the ".WMV" file to YouTube as a target reference for the MuseScore VideoScore.
This is a huge hassle (hint-hint developers) made necessary only because the MuseScore online site does not replicate the audio correctly on the online site. This has been discussed over-and-over and remains unresolved (my largest pet-peeve). The other issue is that the YouTube "Copyright Claim Jumpers" make it necessary for me to constantly dispute invalid claims on transcriptions/arrangements of clearly public domain works. I sure hope this get fixed in my lifetime but in the meantime, the above steps are my workable (albeit time-consuming) solution.
Hope this helps!
Thank you :)
And my name it's right 2 :)
This sounds good.. what program you use?
Apps and the API