Optional fields do not appear in confirmation email (pro-form)

Hello,

I added several optional fields in the registration form for invoice-info.

When I implement those fields with %%field_name%% in the mail-format from the confirmation email (pro-form) , they give empty result when the mail is sent.

The strange thing is, the fields do appear in the Modification Confirmation email (Pro-form)

Thank you for helping met out here!