How to setup MAXIMA for a web application running on IIS?



Dear all,
I want to develop a mathematics education site that behaves like?http://calc.matthen.com/?.
I will use a Microsoft web technology named ASP.NET MVC 2 that is running on a Microsoft web server engine named IIS 7.5.
My problem is?
how to call maxima from within my ASP.NET codes ?how to isolate each visitor input from other visitor inputs such that any bad input from a visitor cannot interfere with other visitor inputs.
Thank you in advance.

regards,
yoyo