David,
You should be able to put our login Easy-tag into the module with the following code
I'm not familiar with a separate login module for the Kunena component. However, you should be able to put that Easy-tag 1) in whatever template overrides you create for the module, or 2) if there are any parameters in the module for adding your own text (e.g. Joomla Users login module has pre-text and post-text fields).
If you'd like to see more parameters for the easy-tag, go to JFBConnect backend > Social > Examples.
-Melissa