Will FES Use Custom Fields?

Hi:

The FES (front-end submission) documentation says that only the standard WP post fields are supported. But it also says we need to create a metabox first - which can have any number of fields.

So, the question is, will the FES module allow you to create FES forms that have custom fields in it or is it restricted to just the standard post fields (title, content, except, date, thumbnail)?

Thanks.