Artillery machines modding please help

Hi to all

I am trying to add the ability to the Greek Cities to produce scorpions (the artillery machine that only Romans use) but I can not find the record in the escr_model_battle file. I have already include in the Greek arsenal the ability to produce Macedonian Cavalry and Tracian bastanaes. At this point I would like to add that in the fist case (Macedonian Cavalry) moding of the escr_model_battle is not needed and that the units figure in the game (strategic map and battle map) is not a grey peasant but the Macedonian Cavalry. Please help.