I think that in your case the simplest solution would be to have your PHP code directly send events to Lightstreamer Server through ARI (Adapter Remoting Infrastructure). In this case you wouldn't need to code anything in Java and to integrate PHP with Java.
In other words, you should develop a Remote Data Adapter in PHP, which can live within your web server. The picture below shows this architecture.
To achieve that, you should first become familiar with the typical workflow of a Data Adapter, by referring to section 4.2 of "General Concepts.pdf" and to the "Hello World" tutorial. Then, you can start developing your own remote PHP Data Adapter by working at TCP socket level and referring to "ARI Protocol.pdf" for the socket protocol documentation.
Hope that helps.
