J´ai trouvé la solution par moi même, alors je vous la donne:
D:\Program Files\sixteen tons entertainment\Emergency 4\data\Specs\freeplaybase
Changer toutes les dernières valeurs par celle ci par exemple vous aurez 20 camions de pompiers, ambulances, polices et EDF.
<freeplaybase>
<vehicle
prototype="mod:Prototypes/Vehicles/Ambulance/nef.e
4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Ambulance/rtw.e
4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Ambulance/rhf.e
4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Ambulance/rhc.e
4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Ambulance/itw.e
4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/rw.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/tlf.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/gtf.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/dlk.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/lpf.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/dekonp.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/tfmb.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/lf.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Fire Department/flb.e4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/stw.e4p"
count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/mtw.e4p"
count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/Police/sw.e4p" count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/phc.e4p"
count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/gtw.e4p"
count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/waw.e4p"
count="20" />
<vehicle
prototype="mod:Prototypes/Vehicles/Police/getawayc
ar.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/TEC/fgri.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/TEC/fgr.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/TEC/fgr_t.e4p" count="20" />
<vehicle prototype="mod:Prototypes/Vehicles/TEC/asf.e4p" count="20" />
</freeplaybase>
Voilà l´intégralité du fichier XML, servez-vous!!!!