Hello Tomsch1,
Thank you for contacting National Instruments.
You can you use DDE to send messages to mirc if mirc supports activeX. Below is a link to an example VI using DDE to write to an Excel file. You can use this as a starting point and replace the Excel calls and commands with those appropriate for mirc.
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B123AE0CB9F2111EE034080020E74861&p_node=DZ52049
I hope this helps,
Sean C.
Applications Engineer
National Instruments