How can I change the screen resolution of Slax?

Slax uses X.org for managing its GUI. However, when I boot Slax (specifically in a VM), the resolution gets capped at 1024x768. How can I increase the resolution to more fully utilize the screen estate available on my display? I have already attempted to follow the old advice from the following sources: - http://old.slax.org/forum.php?action=view&parentID=25516 - http://www.linuxquestions.org/questions/mandriva-30/changing-screen-resolution-552768 - http://slaxlive.blogspot.com/2005/07/slax-linux-step-by-step-first-step.html