Urdu/Arabic script rendering is not correct

I have used three Arabic true type fonts, two of which are not displayed
correctly in qt4/kde4/koffice2. Openoffice 2.3.1 and KDE3, however, display
them correctly (well, KDE3 has minor issues with one of them, too). The two
fonts that simply don't work at all in qt4 are "Nafees" and "Aleem Urdu
Unicode". The former is created for the specificities of the Urdu version of
Arabic script, called Nastaliq. Nastaliq is written in a cursive manner; i.e.
its characters combine with each other and therefore they are written not
only from right to left, but also somewhat from top to bottom, thus making
the rendering quite difficult. The second font that is not displayed (Aleem
Urdu Unicode), however, is a Naqsh font (that is, a standard Arabic font,
that is NOT written from top to bottom like Nastaliq). A third font, "PakType
Tahreer", is displayed perfectly in the qt4/kde4/koffice2 environment. [Just
as a side note: this font is the exception. Most Arabic fonts are NOT
rendered correctly, if at all. However, I had to reduce the scope of this.]