The Causal Principle does play a role in the kalām argument: it undergirds the argument's first premise.

The basis for the argument’s first premise is the Causal Principle that undergirds many cosmological arguments. (Oderberg [2002: 308] is mistaken when he tries to establish the uniqueness of the kalām argument by denying that the Causal Principle plays a role in kalām argument. It only does not play a role in supporting a particular premise in the argument.) Defenders and critics alike suggest that basing the argument on the Principle of Causation rather than on the more general Principle of Sufficient Reason is advantageous to the argument (Morriston 2000: 149). Craig holds that the first pre...