Name Field Problem

Hello,
i create a form with CF7 with “firstname” and “lastname” fields.
The plugin has only the “name” field and i cannot send to Getresponse both field.
How can i solve this problem?

I tried to create a custom field with surname but Getresponse don’t see it in the search field when i search “surname”.

I must have both field in the CF7 form (first name and surname), not 1 field, i and i need to send both fields to Getresponse so Getresponse can create the Name field with both fields, first and last name
Thanks!