network_site_new_form usage

Hi,

Simple question for “mutlisite install” :

I would like to add input to the “create a new site” form in the network admin area.
Since 4.5 there is a hook called “network_site_new_form” which is perfect to ouput new html in to the form.

But i can’t find any other hook to handle possible new POST data i might have if i had field to the form.

Any help appreciated 🙂

Benoit