I've never used Net::IRC, but from the POD and your description it sounds like it invokes an event handler. It would appear that you'd have to create an on_event sub to suit your purposes. Alternatively, you can implement your bot in IO::Socket::INET, which makes this problem trivial.

User actions have \001 prefixed and appended to the action-text.

UPDATE: Net::IRC includes the addfh() method, which if you can use to add the new() socket, you can also register your own callback sub. Alternatively, you can use the add_handler() or add_global_handler() methods -- the documentation is particularly sparse, but it appears that it only responds to IRC server responses as defined by the RFCs.