You could do it as a custom hook in the FormIt snippet or with a snippet.
Creating a resource in code is as simple as this:
$createdBy=$modx->user->get('id');
$flds = array(
'pagetitle' => $title,
'longtitle' => $longtitle,
'description' => $description,
'introtext' => $introtext,
'alias' => $alias,
'parent' => $folder,
'createdon' => $createdon,
'createdby' => $createdBy,
'editedon' => '0',
'editedby' => '0',
'published' => $published,
'pub_date' => $pub_date,
'unpub_date' => $unpub_date,
'deleted' => '0',
'hidemenu' => $hidemenu,
'menuindex' => $mnuidx,
'template' => $template,
'content' => $header.$content.$footer
);
$resource = $modx->newObject('modResource',$flds);
$resource->save();
You can also set individual fields with:
$resource->set('fieldName',$value);
BTW, I’m working on a Revolution conversion of the old NewsPublisher snippet, which may do what you want, but I don’t know when it will be available.