(POSSIBLE SPOILER)

I tried to complete this quest in a peaceful manner... but its impossible. I have tried multiple;
* Speaking to General Tullius.
* Wearing an Imperial Officer Helmet.
* Wearing an unique full faced Imperial Helmet.
* Have an entire set of Imperial Armor on (including the mentioned helmets).

Now, after researching a bit it seems like there are a few objects made by Bethesda that has a connection to this quest, such as a note... however this note does not appear in the game, also heard rumors of wearing Imperial Armor... an unique version, but it seems like it does neither appear in the game.

Is this just an unifinished quest?
Is it bugged?
Is this actually the way its suppose to be; bloodshed or sneaking is the only option?

Any information about this would be appreciated...

Bethesda was going to make that note but it was scrapped so try this......kill your way to thorald gray mayne,worked for me