Etherchannel support was introduced in ASA 8.4(1) software.
See the configuration guide. It has some guidelines and caveats for using Etherchannel interfaces for failover as follows:
Failover Guidelines
•When you use a redundant or EtherChannel interface as a failover link, it must be pre-configured on both units in the failover pair; you cannot configure it on the primary unit and expect it to replicate to the secondary unit because the failover link itself is required for replication.
•If you use a redundant or EtherChannel interface for the state link, no special configuration is required; the configuration can replicate from the primary unit as normal.
•You can monitor redundant or EtherChannel interfaces for failover using the monitor-interface command; be sure to reference the logical redundant interface name. When an active member interface fails over to a standby interface, this activity does not cause the redundant or EtherChannel interface to appear to be failed when being monitored for device-level failover. Only when all physical interfaces fail does the redundant or EtherChannel interface appear to be failed (for an EtherChannel interface, the number of member interfaces allowed to fail is configurable).
•If you use an EtherChannel interface for a failover or state link, then to prevent out-of-order packets, only one interface in the EtherChannel is used. If that interface fails, then the next interface in the EtherChannel is used. You cannot alter the EtherChannel configuration while it is in use as a failover link. To alter the configuration, you need to either shut down the EtherChannel while you make changes, or temporarily disable failover; either action prevents failover from occurring for the duration.
Hope this helps.
