ich glaube dir fehlt das:
plugin.tx_srfeuserregister_pi1.formFields = username, password, gender, first_name, last_name, status, date_of_birth, email, address, city, zone, static_info_country, zip, telephone, fax, language, title, company, www, module_sys_dmail_html, module_sys_dmail_category, image, comments, disable
