Subscribe with Firefox using the "Try" view?

I’m using the subscribe with newsblur option from the goodies section, in Firefox.  When I do this, it brings me to a newsblur window with a tiny window in the lower left for confirming/actually adding the feed.  It’s not terribly useful.

On the other hand, the recommended feed section on the home page presents a “try” interface, e.g. which gives me a full preview of the feed content _and_ a subscribe button at the bottom.

I’d like to register this view as my Firefox handler, but the Try view seems to need an ID rather than a URL.