SOAP Action Header is sent Automatically, no user input is required in terms of that.
In order to control your devices via IP using SOAP action you will need to know the following:
1. Control URL
2. XML String
3. Port number from control URL
All of the above should be in the control protocol documentation of your device.
For example Sony BD player's command for Home button is:
<?xml version="1.0" encoding="utf-8"?><s:Envelope s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body><u:X_SendIRCC xmlns:u="urn:schemas-sony-com:service:IRCC:1"><IRCCCode>AAAAAwAAHFoAAAA9Aw==</IRCCCode></u:X_SendIRCC></s:Body></s:Envelope></Code>
So you would copy the command just like above into the builder under NETWORK CODES.
In the app, you would setup a HTTP GATEWAY with POST method. You will then need the Control URL info. Sony's control URL is /upnp/control/IRCC and port number is 50001.
So your gateway setup in the app would look something like this: