Personally, I did it in game via the #spawn command.
Race 41 is a Vendor, and merchantid (the last field) is the merchant's wares listing as seen in FQAdmin's browser. The rest are changeable.
Example:
#spawn (NPC Name) (Race) (Level) (Texture) (HP) (Gender) (Class) (Primary Weapon) (Secondary Weapon) (Merchant ID)
#spawn More_Paladin_Spells 8 70 3 10000000 1 41 0 0 5032
Will spawn "More Paladin Spells" a Dwarf (Race
, Level 70, in plate armour (Texture 3), with 10million hp, Female (Gender 1), Merchant (class 41), with no visible weapons, and Merchant Wares taken from the data listed as merchant_id 5032.