Unskinning CAknSearchField

This call:
m_pFindBox->SetSkinEnabledL(EFalse);
doesn't seem have any effect on the Find box of my listbox.
The findbox is still skinned and has a white box on top of the skinned text entry region.

Is there more involved in unskinning an CAknSearchField object belonging to
an CEikColumnListBox?

I am trying to unskin the findbox because of a ghosting artefact I am seeing
when BaseConstructL(CAknAppUi::EAknEnableSkin) is enabled.

See:
http://discussion.forum.nokia.com/forum/showthread.php?t=123907