How to setup SSL with SNI feature for Domain Mapping plugin?

Hi, I am trying to install two SSLs, one for and the other one for, but when I install the second one it overwrites the first one. I am using this site to check if it is working or not:

Bluehost has given me this url for fixing that:

Would that work? Is it really that hard to get it working? The access is already granted and if my WHM and server credentials are needed, just let me know. Thank you!