Greetings for the Day!!
I am taking ownership of this Issue and will be assisting in dealing with your query. The Issue will be managed according to the Impact/Priority levels you have requested.
For more information about BMC Support Service Levels and definitions for BMC Support Severity Levels please see the link set out in my signature below.
Your request to add the custom fields in the ITSM universe is purely a customization and is out of support boundary for us. You can either work on this yourself or contact the Professional Services team who can help you on this request.
BMC Support does not support customization. In this case you will need to involve your customization team. However in case if you need any kind of further assistance regarding the customization you can reach out BMC Professional services which specifically look after customizations and is a paid service.
For your reference please find the contact details.
To contact professional services: