[TYPO3-mvc] Inheritance from FrontendUser not working

[David Schreiber]

Hello Everybody,

Same story like always, this time another problem.

I have inherited my Members Model from the Extbase Model FrontendUser.

class Tx_MmfRrmarket_Domain_Model_Member extends
Tx_Extbase_Domain_Model_FrontendUser {

...

}

I have my Commodities Model with a seller property referring to a
Member object.

/**
	 * seller
	 * @var Tx_MmfRrmarket_Domain_Model_Member
	 * @lazy
	 */
	protected $seller;

When I output one commodity object via t3lib_div::debug it prints
following:

Tx_MmfRrmarket_Domain_Model_Commodity Object
(
    [seller:protected] => Tx_Extbase_Domain_Model_FrontendUser Object
...
...

It seems that Extbase resolves my seller property to the wrong type of
class -  Tx_Extbase_Domain_Model_FrontendUser instead of
Tx_MmfRrmarket_Domain_Model_Member.

How can this happen? Shouldn't Extbase support inheritance from
classes?

Thank you,
David Schreiber