JDBC connections with Instanced database names in NG PRO

Can somebody explain how to configure a database connection for a database that is hosted on:

server\instanceName

 In free version I could make a connection with ease, however in pro version I cannot do it so far.

jdbc:sqlserver://serverName;instanceName=sqlInstanceName;databaseName=XYZ;user=X;password=PASS_VALUE

using this exact same syntax in database configurator I get an error saying that it cannot connect.. and it also forces a port 1433 in the connection string

Also, 

using old test cases with such syntax, I can connect to a database and all jdbc requests can be run, but trying to edit the said connections gives an error "Connection string does not match Connection URL template"

EDIT:

I've narrowed the problem to the connection configuration wizard forcing me to use a specific TCP/IP port for the instance to operate on, which we do not have set up and we use a dynamic address for that instance.

So the next question is, how do I circumvent the need of this software to force the port number in the connection string?

Mind you, without using the port, the connection can be established.. but I cannot configure environments and connection strings without it -.-