Unable to use MS SQL Server named instance in JBoss SOA Platform pre installation

Issue

• I am attempting to connect a MS Sql Server named instance to JBoss SOA-P in our environment.
• I am running the schema script and including the hostname of the instance as HOSTNAME\INSTANCE, however, the slash has been removed from the contents of the mssql-ds.xml file are as below.
• Is specifying the server and instance separated by the slash the correct way to specify it?
• I changed the mssql-ds.xml file and changed the connection as follows, however, on starting the server there are exceptions indicating that JBoss is still attempting to connect to HOSTNAMEINSTANCE:1433 (i.e. ignoring )

 <connection-url>jdbc:sqlserver://HOSTNAME\INSTANCE:1433;DatabaseName=soa</connection-url> 

• Contents of mssql-ds.xml:

...
        <connection-url>jdbc:sqlserver://HOSTNAMEINSTANCE:1433;DatabaseName=soa</connection-url>
...
</datasources>