Need help with symbol synthesizing in Yakuza Ishin.

Hi! I hope there's some helpful souls who has played Yakuza Ishin before.

I'm trying to understand how symbol synthesizing works. So I tried to follow Khhsubs guide ( http://www.khhsubs.com/rggishinblacksmith.html ) and transfer a weapon Enchantment symbol (life absorb) to an empty slot of another weapon (specifically Kinshinmaru the DLC sword because it has 3 empty slot) but when I tried it in battle, it doesn't work. I even made sure that I get the synthesizing mini-game perfect.

I also tried transferring Thorn symbol (imbues sword attribute to hand-to-hand combat) to my highest tier gauntlet, equipped a weapon whose default attribute is Enchantment and tried using unarmed combat in battle. The Thorn symbol did not pickup the Enchantment symbol like it's supposed to. No life absorption at all when attacking.

I wonder if anyone here knows the limitation of symbol transferring because I've been trying for the past 2 hours experimenting without results. I wonder if I should ignore symbol transferring and just use a weapon's default symbol. Or if Thorn symbol is absolutely useless.