[Plugin: Collapsing Categories] Adding additional icon (and code) after RSS feed icon

I’m planning to syndicate a number of feeds from a WordPress blog (mostly categories) via Feedburner. I’d like to add an additional icon and code immediately after the RSS link that Collapsing Categories puts after the category names. The code would be a link to Feedburner’s subscribe by e-mail feature.

Can you point me to where in the code I’d have to do this? Or, even better, has anyone done this or something like it?

Thanka!