Okay, just thinking off the top of my head here, brainstorming.
If the musical notation is available as a PD font, would it be possible to embed the font? Because then you could "break" the musical notation pages into 3 images. A smallish left image (3-15 pixels or whatever), it's mirror image for the right side of the page, and a middle image 1 pixel wide and however many high, set to be repeated.
Now that the musical bars are accounted for you can "type" the musical notation on top of these images, along with the song lyrics.
The only other thing that I can think of is to take a look at some musical software that offers printing of musical scores to see how they handle things. Particularly any websites that provide similar features. Any such site is dealing in HTML and you're not much different. You might find some creation tips there.
Not sure of it's status / usability for this, but this
music symbol font might be of help. Assuming this font is no good, try the music sites first (they are more likely to have what you want), then free font websites.