[TYPO3-mvc] updateAction not saving field extending another Model

[Søren Malling]

Hi,

I've created a Model extending the FrontendUserRepository

class Tx_Groupmembers_Domain_Model_Member extends
Tx_Extbase_Domain_Model_FrontendUser {
.....
}

and added the field in ext_tables.php and ext_tables.sql
(tx_groupmembers_domain_model_number) and it's shown perfectly in the
backend.

In my frontend, I can't get the content of the field nor save to the field.

In my model the field is described as

	/**
	 * Member number
	 * @var string
	 * @validate NotEmpty
	 */
	protected $number;

and my updateAction is as follows

	public function updateAction(Tx_Groupmembers_Domain_Model_Member $member) {
		$this->memberRepository->update($member);
		$this->flashMessages->add('Your member details have been saved');
		$this->redirect('index');
	}

and I got setters and getters for the field. But nothing is updated in
the database.

When i print_r from the form i get the following value for the  field
[number] => 23 but wouldn't that be tx_groupmembers_domain_model?

So in short, what is the correct way to name a field extending a
table, in my model?

Regards,

Søren