You need to authorize the transaction with signatures for both accounts. 1. The ressource-paying-account and 2. the acting account.
Assuming that lionstester1010 should pay for the transaction but lionstester1011 is the acting account/the sender of the token:
There was an opened issue in the repository. It was fixed today. You can get the updated eoslime code from the development branch. The fix is going to be uploaded on master branch and npm through the next week
Steemit currently has a similar functionality, I would look at their coding, as it will be very similar to EOS. Specifically in steemit see: https://steemit.com/steemit/@adept/tutorial-how-to-sent-and-recieve-private-encrypted-messages-on-steemit