You need collect 4 scroll which scatter in broken valley, take them to the gremlin which at the entrance of maxos temple for translation and you get the password for the portal
I found all four scrolls, but somehow during my travel, one went missing. And no, it wasn't because of a reload. I had saved. I've had other items removed, also. Frustrating.
But are you sure you pick up all scrolls? Maybe by accident forgot to pick up one?
But when items disappear out of your inventory, very strange.... !
On 7th of february 2015 : I start a new adventure in the Divinity world of Original Sin, it's a Fantastic Freaking Fabulous Funny ... it's my All Time Favorite One !
Anyone know where all of those portals that require bellegar for password are, I know theres more then one in Broken Valley, cant remember where i seen them tho.
The other teleporter is near Lovis' tower. From the shrine area where you first meet Talana, head south across the nearby bridge and the teleporter is off to the left.