The HA document does not require the specificaiton of wka port and localport for coherence, but if you would like to create multiple SOA HA domains, You have to use different coherence settings for these domains,

For SOA Domain 1 , set the following properties in the weblogic server startup argument.

-Dtangosol.coherence.wka1=apphost1vhn1 -Dtangosol.coherence.wka1.port=<port1>
-Dtangosol.coherence.wka2=apphost2vhn1  -Dtangosol.coherence.wka2.port=<port1>
-Dtangosol.coherence.localhost=apphost1vhn1 -Dtangosol.coherence.localport=<port1>

For SOA Domain 2 , set the following properties in the weblogic server startup argument.

-Dtangosol.coherence.wka1=apphost1vhn1 -Dtangosol.coherence.wka1.port=<port2>
-Dtangosol.coherence.wka2=apphost2vhn1  -Dtangosol.coherence.wka2.port=<port2>
-Dtangosol.coherence.localhost=apphost1vhn1 -Dtangosol.coherence.localport=<port2>

<port1> and <port2> must be different.