I have two ASA devices. 5510 with IPS and 5520 with Content scanning. The 5510 sits behind the 5520. I want the 5520 to perform all firewall functions along with content scanning for spyware and viruses. The 5510 will be used purely for IPS for traffic that has been allowed through the 5520. Is there a way to effectively turn off the firewall on the 5510? Is there any inherent problems with this configuration?