You could use either Microsoft VOLT or FL 5.1 and with the latter you have to change the kern code, because fontlab doesn't generate kern for right to left scripts yet. but with VOLT it's pretty straight forward, just generate the font in fontlab and import it in VOLT. there is adobe arabic VOLT file that could demonstrate how it works:
http://blogs.adobe.com/typblography/2007/06/adobe_arabic_sa.html