add custom fields to Excel export from resource view

We use the resource view export (in Excel) to generate forecast reports on expected effort-level in the future. This effort can be assinged to either assignees (User) or job-roles (Placeholder).

By using Excel pivot-tabels these reports give a detailed insight to our management team in projectstatus like order- and offerlevels and occupation on our departments in the future.

For us it would be helpfull if custom field values could be included in the export.