This functionality can be accomplished by the following..
1. create an access list to define your interesting traffic
access-list mycapture extended ip host 172.16.0.1 host 172.16.0.2
2. make your packet capture using the ACL..
capture mycapture access-list mycapture buffer 2000000 packet-length 1518 interface inside
3. download the capture from the ASA by connecting to it using https
https://192.168.1.1/capture/mycapture/pcap
this downloads the capture in a form that Ethereal can use..
4. Analyze your capture using Ethereal...
This is a really nice way of looking at desired data... Thanks Cisco!!
If this helps, please rate.
Cheers.
Jay Walker