Call recording in asterisk

[andu]

Hello!I am new to asterisk and I am having an issue about recording calls.
I have a web based gui written in java,I can make a call in an automated way such that when I click a button in GUI it makes a call from softphone with extension 1000 to extension 1001.
I made this using AMI -asterisk manager interface,I have the asterisk running in a server in the same network as the application.
I hace seen that it is good if I want to record a call to call an AGI script.My problem is that using another button in GUI to have the opportunity to record the `call which is in process.So I can start or stop it.
In free PBX i have configured onDemand for call recording (with feature code *1).
So my problem is that I want to call an AGI script that has code for recording the call that is in process.Also how to include AGI script to AMI?