Hi,
Let me first mention, that you can simplify the process and give the user the possibility to fill the form directly on the Self-Service Portal thus generating a Service Request with the data. This will be a major time saving for your ICT team. Of course,
if the SR must be generated from the console, than my suggestion does not apply :)
Now back to extending the class... If I understood you correct you will have to generate Service Request, not Incidents..So in this case you will have to do two things:
1. Extend the SR class with the new custom property (properties)
2. Extend the SR form with a field (fields), which will be populated by the new properties
Let me mention, that if the properties you need can be taken from the CMDB, then you don't need the first step.
Below I have posted a couple of articles, which should give you an overview on how to achieve your goal. Note, that the process of extending a SR or an IR is the same.
https://kareembehery.files.wordpress.com/2013/12/extend-the-service-request-class.pdf
Extending the Service Request Form and Exposing the Request Offering Field in System Center 2012: Service Manager
http://blogs.technet.com/b/wincat/archive/2013/03/11/extending-the-service-request-form-and-exposing-the-request-offering-field-in-system-center-2012-service-manager.aspx -
Here only the SR form is being extended
Use VIP support in service manager
https://dynamicdatacenter.wordpress.com/tag/extend-incident-class/
You can watch a video from a Travis Wright on extending the incident class and for and apply the same approach on SRs:
https://www.youtube.com/watch?v=b5RSGAPwA9E
Hope this helps. Regards,