CAS endorsed FIFA's initial verdict against Ismaili, who failed in their appeal to keep the International Transfer License of the 25-year-old midfielder.
Abd-Rabou spent the past couple of seasons on loan at Ismaili, but the Dervishes failed to pay the player's permanent transfer fee of €500,000 on time.
Consequently, Strasbourg are obliged to return the amount to Ismaili, who missed the deadline of June 15th 2007.
Ahli Stance
As a result of the decision, Ahli now have the right to own Abd-Rabou as the CAN 2008 Player of the Tournament has already signed a contract with the Egyptian champions.
The Reds will be allowed to finalize the deal with Strasbourg after Ismaili pulled out of the tussle.
Despite not making any official declaration regarding the new effects of the situation yet, the Reds' board are expected to discuss the case on Thursday.