How do you change an existing component to an envelope using API? This functionality seems to work using the GUI (http://help.solidworks.com/2014/English/SolidWorks/sldworks/t_Creating_an_Envelope_from_a_Component.htm).
The only obvious envelope API that I was able to find are the InsertEnvelope and IsEnvelope methods of IAssemblyDoc. The insert method needs a file name and will create a new envelope component from that file.
When capturing the GUI functionality with the macro recorder, it shows CompConfigProperties4 function with 7 parameters - the last which seems to control the "envelope" flag/checkbox. However, CompConfigProperties4 only has 6 parameters and running the macro back fails because of that.