I'm not sure about my English wording - would you say it renders the Russian more or less accurately?

I'm not sure, but one version I've seen is "The party said: "There's a necessity!" — The Komsomol answered: "Yes!". Another possible answer is "We will".

Thanks. OK, I'll embrace some of your suggested solutions.
Regarding "Yes" or "We will", are you sure it renders properly the expression «Есть!», which literally means "there is"?

@Eldad: https://tatoeba.org/rus/sentences/show/4518359

Dankon, mi jam vidis vian version, kaj helpiĝis de ĝi en mia korektita versio.

In this context "Есть" rather means something like "yes, sir!" and means that you understood the order and will do it. It's commonly used in the army.

Thanks. I hope my current version conveys it properly. What say you?

Now it's close to the original sentence but I can't judge how natural is it.

"Есть!" is something, that military people answer to the order they get. It means they take the obligation to fulfill the order. So, the best solution is using the same word that English speaking military people use.

http://www.dicipedia.com/dic-ru...term-10685.htm
воен. yes, sir!
есть, товарищ генерал! — yes, или very good, comrade General!

We don't have to worry about that. ;-)
There are enough native speakers who won't hesitate to comment on my sentence. ☺

Thanks, Selena and Marina.
My last comment referred to odexed's reply.
Got that, regarding the "yes Sir!" as in the army. I hope my current English version reflects it properly.

Maybe then: "At your command!" will also be appropriate here?

You're welcome, Eldad.
In opinion "Надо!" is rather "It must be done" here, than "It's nesessary", but i'm not a native.

Thanks, Selena. I added another variant with a wording that suits your suggestion.