Can PHP Connect to an OPC Server?

I'm having a difficult time finding out if PHP can connect to an OPC server, and how. Our PHP is running on Unix with an Apache webserver. The OPC server is on Windows, that's the most I know about it at this time. Both servers are on the same network.

Research:
QuickOPC-COM requires a Windows-based server.

If you can communicate via XML-DC, then you should be able to use the SOAP client in PHP. Check out the WSDL for OPC. I wasn't able to find much documentation, but take a look at this post...

Also, this thread may be of some insight...