How do we access properties through liquid tags?

[dcorsus]

So I can call functions like this:

  The follow demonstrates how to call custom functions in your plugin using tags<br />
                          Custom function value:{{ plugin_function 'HomeSeerSamplePlugin' 'MyCustomFunction' ['1'] }}

How do we call or set properties? The plugin_function subsequently calls PluginFunction but I need access to PluginPropertyGet.

Thanks,

Dirk