Scion/Jara Cave PSG1

I remember how to get the Palma key that opens up Medusa/Island Tower dungeons. I however can't get that key yet, I think I need the Scion/Jara key first before it triggers the event to get the it. Does anyone who played PSG1 remember?

Yeah, you should do the Jara cave, but I don't know if it's required. Do you have the hovercraft and stuff?

You do need to go to Sopia and then do Master Tajima's cave. He tells you about going to Bortevo for this, I think. After Tajima, Go talk to the guy in the house in NW Bortevo, and he tells you the key is under a tree in the town (by the SW ruined house).

I found a site in Portuguese featuring the best walkthrough I've found for the game. Sure has come in handy, since while I know the SMS version inside out I've gotten stuck a time or two in this one since of course, I don't know Japanese. Using Google Chrome works great for that site, since it will translate the Portuguese into English right on the page. Apparently I can't post the link here since my account is new or something.