Hi Stefano,

Sorry, but it's not possible in Form Builder in the current version.

If you need this feature in next days/weeks, I guess you have to use different form extension, then use a module from it inside SPPB. Check product from tassos.gr.

Thanks for the reply. Can you recommend something to implement this function?

As I said before: Convert Forms (tassos.gr)

thanks but i was looking for something free.

But it has free version as well.

Besides it was one of many form/contact extensions for Joomla, just search on JED.