assuming the 3rd party app is using setresult(), you'll be fine.
i don't have a particular example in mind, sorry. there are plenty.
just type "activityforresult" in the search box. find a recent one and run it.
if it runs, and you follow what's going on, you'll be able to adapt it. if you
get stuck, i'm happy to tell you what i see. erel has set this particular
routine up to work very easily (as is usually the case). 2 or 3 little pieces, and
you're good to go.