you can't set additional props/evars/events out-of-the-box. that means, they are not handled like "normal rules". instead, they are just triggered by the analytics extension if you check the boxes.
as far as I know there are 2 workarounds you could try:
"custom code in analytics extension"
add doPlugins (which is run in every event) and check for "linkType" equals "d" (download). if that's the case, set all the desired props/evars/events.
thats the solution we use in our implementation.
"custom code to trigger a rule"
Don't know the details how it works. basically you do the same as above (check for download event), but instead you "abort" the tracking and call a custom rule by using _satellite.track("ruleTrigger"). now you can setup a rule with the same trigger as condition and set the actions similar to any other rule.
Remark: if you have more questions regarding Launch, I suggest to post them in the "Launch" section of this forum...