Non-state change action in custom work item

Work flow for a custom work item only supports state change actions. I'd like to have a "work item save" operation participant perform some external actions when a user performs a non-state change action on a custom work item. The non-state change action may involve attribute changes. Also, I have more that one such non-state change action that I need to present to the user. Does anyone have a suggestion on how I might implement non-state change actions for a custom work item?

Thanks,
Geoff Alexander