Thanks for your interesting.
About Lacantia\Licentia I've checked out a lot of small village near S. Stefano but no one has this name.
But I know in Latin "licentia" means something like
"permission". And Mai (or Maii?), means "may"\"of may"...
So, "licentia maii" maybe can means "permission of may"
Does it have any sense for you?
The best naturally would be to see the document :(
Sorry for my bad English.