What's the batch file doing exactly? Most of the commands in a batch file can be reproduced in mIRC directly. You can also use run -n <command> to execute single commands that mIRC cannot do itself. Unless it's a long complicated batch file you may be able to translate it into mIRC code.
One way to get a batch file to get a message to a channel through mIRC is if you had some sort of DDE utility. I'm not aware of any command line DDE utililtes though.
