Revert "Correct naming for Custom Fields"

This reverts commit c2098656caab709648c77bf9a4ee57cf4bc7d65e.

Hi Jiri,
I'm very sorry about this but it would appear that I got this patch wrong.  Please revert it.

While the hyphen does work, I left in the curly braces which is incorrect for that format.  It turns out what you had coded originally worked and, according to the limited information I could find in the RT forums, is possibly more forward compatible.

My apologies.