Theoretically, yes. Will it always work? No.
Step one: add the upload or link logger to your profile, so they can select where the file is at.
Step two: This URL (if it's an upload, it'll be a local URL) will then be put into an <embed> tag so you can put the MIDI in the page. If it's MP3, you may need to run it through a special plugin.
Hey, you're done... try looking up embedding MIDIs in HTML files, or look at the sourcecode to the place you were talking about.