After reading the documentation regarding the NIC cards on the ACS appliance it seems the both cant be used together. Can one be used as a management Interface like on CS-MARS and IPS? while the other performs its normal operation?
unfortunately no, you can only use one NIC that too bottom NIC (NIC 1).
If you want such a feature, you may want to contact your AM, and go for a feature request on this product.
Please rate if it helps!