Hercules support 2ways of adding shops first one similar to what you said
<map name>,<x>,<y>,<facing><TAB>shop<TAB><NPC Name><TAB><sprite>,<itemid>:<price>
also there is another way to do it using trader type, you can check the documentation at https://github.com/HerculesWS/Hercules/blob/master/doc/script_commands.txt#L309-L330
and for some samples check https://github.com/HerculesWS/Hercules/blob/master/doc/sample/npc_trader_sample.txt