Help me fix configuration of php on server accessing microsoft SQL server

My setup is as follows. I have two webservers, one hosting a microsoft SQL database (A) and another, simple web server (B). On the server A I use a php script to interact with the database (simple CRUD operations). This php script provides a web API allowing me to remotely retrieve, create, update.. data inside the microsoft SQL database. Because of security reasons I don't allow to send http requests directly to server A. Instead I rely on server B to receive the http requests from the outside world. These http requests are then forwarded to server A and so on. We can say that server B acts as some kind of proxy for server A. The service I wrote in php has been tested thoroughly and worked perfect with a mysql database. Now however, I want to interact with the microsoft SQL database on the server. Because of some configuration issues with php I can not access the mysql database yet. For this project I want you to help me to establish connection between the php script and the database. I also want to test the forwarding done by server B. For someone experienced with configuring php, this can be a task done in 10 minutes, as everything is already in place and only some small changes will have to be made. I want to have a remote session using gotomeeting or teamviewer so that you can fix the setup using my computer (as access is only allowed for my machine).