Soundfonts When Uploading?

So I am working on a piece and currently using the Fluid soundfont. When I upload the piece however, it goes back to it's cartoony, Musescore-y sound. Which is fine, I guess. Doesn't sound too bad-ish.

I was just curious as to whether or not there's a way to upload the soundfont with the piece or is the soundfont only for when you're working on the piece and Musescore.com itself uses the same basic soundfont for all the pieces on it?