There is a document included with the product named APG-Web-Service-Tutorial.pdf It describes the SOAP API available on the platform. It has details on how to reproduce reports and get raw metric data.
To use raw metrics, will need to understand the metric and property values for the data you wish to obtain. The easiest way to do this is to review the reports in edit mode for the data you want to pull.
You can find the info in APG-Web-Service-Tutorial.pdf in the Doc folder of an SRM install
I was able to locate the file on my unix system in this folder:
Also if you click on "Administration" at the top right of the screen when you login. Then "Physical View" from "Centralized Management" in the middle of the screen. Then the name of the front end server in the left hand pane. Then "SolutionPacks & Modules" tab in the center of the screen. Then "APG-Web-Service". The document you are looking for will be close to the center of the screen under documentation. The application is setup similiarly for other modules. Also there is occasionally documentation PDFs in the upper right hand corner of the sceen when you navigating through menus. Best of luck.