It's not explicitly supported, but the undocumented CallStack property of the Builder component does return an array of strings in the form:
<step type>;<step index>
for each step in the stack.
http://www.kinook.com/VisBuildPro/Ma...peproperty.htm
http://www.kinook.com/VisBuildPro/Ma...psproperty.htm
http://www.kinook.com/VisBuildPro/Ma...emproperty.htm