Cisco ASAs support a version of netflow called NetFlow Secure Event Logging (NSEL). Is special support for the protocol required on the collectors to view the flows? Is the protocol compatible with traditional netflow collectors? In my implementation I am planning on only sending the successful flows to the collector.
Our ASAs (version 8.2(x)) send to a SolarWinds Orion collector using Netflow version 9. We didn't have to do anything special to get it to work. SolarWinds has a doc with a good explanation of the differences between "normal" and "ASA" Netflow here: http://www.solarwinds.com/documentation/Netflow/docs/understandingciscoasanetflow.pdf.
If it helps here is a sample configuration:
access-list flow_export_acl extended permit ip any any flow-export destination inside collector_IP_address 2055 flow-export template timeout-rate 1 flow-export delay flow-create 15 class-map flow_export_class match access-list flow_export_acl description Netflow class flow_export_class flow-export event-type all destination collector_IP-address
NSEL records are only sent during flow creation, teardown, or ACL deny events and utilizes NetFlow v9 fields and templates. Here is a Doc that Cisco has about Netflow on the ASA and at the end it talks about collector interoperability. I personally have used Scrutinizer and everything worked perfectly.
Edit: Also Plixer did a "deep dive" on What NSEL is.