Hey there people. I've been stuck on this quest for a very long time now and I have exhausted all the attempts I could think of to resolve this quest, those being:

Wear a full set of Light Imperial Armor
Wear a full set of Heavy Imperial Armor
Wear a full set of Thalmor Clothes

Join the Imperials and talk to General Tullius
Raise my rank to Legate with Imperials and talk to General Tullius
Talk to the Thalmor in Understone Keep (after doing his quest)
Going to the Thalmor Embassy to look for documents

Sneaking silently passed the guard
Calming the guard
Raging at the guard..

Seriously though, none of these attempts has appeared successful. Does anyone have the answer to resolving this quest peacefully?

Elderscrolls.wikia.com seems to imply that there was supposed to be an option to do this peaceably but it never made it to the final game.

Yup, another thing left out. You have to take out everyone.

Not a problem for me.... I LOVE offing Thalmor.

Does anyone have an offical answer to this? The guide seems to think you can stealth past the guards. The wiki seems to think you need to don imperial legionnaire armor which does not exist. Where they are sourcing this from however is unknown. All I can think of is that this is a bug.. but bethesda support seems to think otherwise.

Perhaps someone from Bethesda can provide the answer?

Everything I've seen about it online points to wearing Imperial Officer armor and talking to the gate guard.

Darn, this is a rather serious bug, luckily my Nord is a total badass, and I managed to slaughter all the guards, luckily I didn't stop to think of a peaceful way for too long if there is none.

The Prima guide says you can stealth past the guards on the way in but they will be alerted if the prisoner escapes. I tried going to General Tullius but he wouldn't do anything for me. Since, I hate the Thalmor, it really wasn't a chore to gut ever single one of them.Though, I only now just realized how OP my character is at lvl 45, I took on that whole fort roughly 5 of them at one time including a caster and managed to survive. Took several well timed pots and some lucky crits but thus far I have not been that deadly under any circumstances.