Joerg,
Dynamic crypto maps can only act as a responder.
Dynamic crypto map entries can have match statments to differentiate which traffic should be pushed.
Initiators that fall under dynamic crypto map can "force" what traffic to push through this particular peer (unless otherwise constrained).
I.e. once the remote end (with dynamic IP) intiates IKE negotiation and the tunnel establishes there will be a binding between which traffic to send and the endpoint IP address(es).
M.