When recording through the Portal user interface, you are provided with a drop-down list box "Select VSE Server:" from which you select the VSE server on which to start the recorder. This is the name that the VSE used to register itself on the registry (so you can have multiple VSEs running on one host, so you can differentiate between VSEs for different projects, uses, locations, etc).
When you have selected the VSE server on which you want to record, the IP address of that VSE server is automatically filled under the "VS Recorder" graphic, so you know which IP address to redirect your application to.
So, it's all about the VSE server when you're recording through the Portal user interface. Your client to this is just a browser, so you don't start any local processes for recording, and you don't even need a local installation of Workstation running to enable your recording.
Record from Workstation: you need Workstation
Record from Portal: you need VSE
Rick