Well, welcome to Business One SDK world.
I don't know what you have to realize but it will be quite hard using PHP - simply because SBO SDK is ( so far ) a .NET dominated topic. Of course you can use PHP for SOAP based communicating with DI Server ( as almost all languages ) but imho it will be a litte bit harder for you. There is only little to no documentation for using B1WS - mainly because it is "standard" SOAP .
You will find some examples in this forum and you have to build your knowledge from that. In the end you just have to get the trick once.
I did my share with PHP and nowadays whenever I have to realize something for web I use a .NET webservice to interact with B1WS. That way I can profit from the .NET WSDL proxy prospects (OOP) and debugging is imho a lot easier.
HTML/JS/AJAX/PHP... -> .NET webservice -> B1WS/DIS -> SBO
If you don't have any experience with .NET then of course it is ridiculous to tell you to learn it..
The more I think about it, I would suggest to send "ready made" xml to DI Server ( via SBODI_Server.Node ). I never tried, but maybe you can access it using PHP directly - this way you "just" have to handle xml data.
regards,
Maik