B4R Question Application that performs http POST with SIM900

This is the first time when I try to write a B4R application! I have an application written for Arduino that has a malfunction and I would like to try a transcript of it. The application must make a POST call to a server using the Arduino UNO and SIM900A. The service on the server works fine. His call is like: http://mysite.com/post?imei=xxxx&v1=0&v2=0
I do not know if there is a dedicated library for working with AT commands or higher level.
Can you give me some advice on where to start?

Thank you!