I am using tinymce as the wysiwyg editor on my site.

I have created a custom css file which tinymce loads to provide me with custom formats via the drop down menu.

I would expect these formats to also be available in the editor when working with html extra fields, this is not the case.

Can someone please let me know how I can add access to additional formatting options within the additional fields system?

Thank you in advance.

Have you enabled the WYSIWYG option in that extrafield?