This is something that has not yet been resolved after the latest patch (the 1.6 versions).
I'm mainly playing Skyrim on the 360 (used to play it on PS3 earlier), so a fix to this issue in future patch releases would be appreciated.
As probably most of the 'Stormcloakers' out there know, after you've finished the battle for Solitude, the Imperials are far from wiped out. Still, the Stormcloak questline is completed.
Galmor and Ulfric will of course encourage you to kill off any Imperials you'd come across in your furher travels, including Imperial Camps (when you ask them "Is there anything more I can do for the cause?")
So, as the topic title says, my main issue is:
Imperial Legates (Camp officers) are unkillable and wrongfully count as murder.
(Same thing applies should you side with the Imperials and decide to kill off any remaining Stormcloak officers)
This is clearly a bug that needs to be resolved.
I hope this is brought to Bethesda's attention.

