I just tried a spanish script developed from Urban Patrol Script. This new script uses buildings (like towers) and static weapons. The most powerful part of this script is the info sharing. Without this script, if you put a soldier in the guard tower (or even into a building), he just stand until he detect the enemy, but it's always too late.
But with this script, the soldiers in the building and towers get information about the enemy from their superior officer, who patrolling in the sector, so they react much realistic.
This is the script name: UPSMON - Urban Patrol Script Mon (search for it in the BIS forum!).