Insert custom thread field into the database

[grey_goose]

This seems fairly straightforward but I guess I'm messing something up.

1. I've added 'expenditure' to the 'post' table.
2. I'd like to be able to to add/update this field when replies to a thread are made.

newpost_process

PHP Code:

if ($type == 'thread')
{
    $dataman->setr('expenditure', $post['expenditure']);
} 


newreply_post_start

PHP Code:

$vbulletin->input->clean_gpc('p', 'expenditure', TYPE_STR);
$newpost['expenditure'] = $vbulletin->GPC['expenditure']; 


newreply_start

PHP Code:

$this->validfields['expenditure'] = array(TYPE_STR,  REQ_NO); 


newreply template

PHP Code:

<input type="text" name="expenditure" /> 


When I look at my post table, there's no values being added to expenditures. I also tried:

PHP Code:

$expenditure = $vbulletin->input->clean_gpc('p', "expenditure", TYPE_STR);
$vbulletin->post['expenditure'] += $expenditure; 


Where am I going wrong?