easy
just extract your media.pk2
then search for RefPrice & RefPackage & RefScarpOf & RefShopGoods all of them are TXTs
then search for an item in item mall already in the same section u want
and take the lines, change the code with ur new item code that u want to add
then add the lines again to ur TXTs
and add it to ur Database side too Tables will be at SRO_VT_SHARD/Tables/...
remember to change the RefShopGoods Slot to the last free slot, so u dont get crash
good luck.