Killzone 3 trophy help?

I got the retro map pack for killzone 3 as there are trophies for the retro pack. I have 1 more trophy and its the one where u have to destroy a sentry turret, sentry drone, and medi-droid in the same round. I was wondering if it has to be on one of the maps on the retro pack? It doesnt specify but it is one of the DLC ones. If u do have to do it on one of these maps which one would be best to get it? I have come so close but its harder than you think..... Help me! thanks