Problem fot integrationwith Vtiger

Hello.
I have done many try for capture lead with Vtiger but i’m not an expert and always give me error.
Can you give me help please?

I can’t undersand what i must put in the function.php

the form is on: https://www.webnet30.com/en/italian-seo-expert-italy-digital-marketing-your-goal-in-italy

here the debug mail.
regards
Francesco

*** Service ***
Array
(
[name] => seoitaly
[url] => https://webnet30.com/gest/modules/Webforms/capture.php
[forms] => Array
(
[0] => 1529
)

[success] =>
[hook] => true
[mapping] => Array
(
[0] => Array
(
[val] => 1
[cf7] => lastname
[3rd] => lastname
)

[1] => Array
(
[cf7] => firstname
[3rd] => firstname
)

[2] => Array
(
[cf7] => email
[3rd] => email
)

[3] => Array
(
[cf7] => description
[3rd] => description
)

)

[separator] => ,
)

*** Post (Form) ***

*** Post (to Service) ***
Array
(
[lastname] => lastname
)

*** Response ***
Array
(
[headers] => Array
(
[content-encoding] => gzip
[vary] => Accept-Encoding
[date] => Sun, 05 Apr 2015 09:14:07 GMT
[connection] => close
[content-type] => text/html
[content-length] => 77
)

[body] => {“success”:false,”error”:{“message”:”Webform not found.”}}
[response] => Array
(
[code] => 200
[message] => OK
)

[cookies] => Array
(
)

[filename] =>
)

https://www.ads-software.com/plugins/contact-form-7-3rd-party-integration/