I am pretty sure You are talking about the "All Ghillied Up" map? I think that if you just wait for the enemy to arrive and let them kill you, the map should restart at the point where you sat Captain MacMillan on the ground. After you get killed, do not exit the game. Then when map restarts, you can situate your clays where you want them.
Luckily I did not have to go to far back - it started me back at the assassination - had to do that 7-8 times (first time did it once). Finally tried a strategy I saw online and got past it.
Thanks, -- Brian
"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain
