Call Virtuemart methods from external script

Question

I want to call virtuemart methods from external script.How can I do that? for example I want to call store() method of a model,how can I do that from an external php file? Thanks I've already done that.I have done successfully upto here,

$user = new JUser;
if(!$user->bind($data)) {
  $status = $user->getError();
}
if (!$user->save()) {
  $status = $user->getError();
}
else {
 $status = "Success";
}
JTable::addIncludePath(JPATH_VM_ADMINISTRATOR.DS.'tables');
$vuser = new VirtueMartModelUser('0');
var_dump($vuser);
$r = $vuser->store($mdata,TRUE);

But I tried to use some methods of Virtuemart,but currently unsuccessful.I dont know how to do that correctly.I'm getting this as blank page.