Insert custom DLL function

Good morning,

I am starting to compile more custom functions. I thought it was possible to have these appear in the "insert function" action. However, these do not show up.  I did stumble on CustomFunctions =  to show the content.

Is this possible?  

This was a note from pre-Prime DLL construction:

Making the function available through the Insert Function dialog box In order to make a function appear in the Insert Function dialog box, you must provide information in the file USER.XML located in the subdirectory \DOC\FUNCDOC. Each function is an entry between <function> tag. Use the <name>, <category>, and <description> tags to specify the function name, its category, and its description as they should appear in the Insert Function dialog box. Between the <params> tag, indicate the parameters the function accepts. If you create a CHM Help file for your functions, use the <help_file> tag at the top of the XML file to provide the CHM filename. Use the <help_topic> tag between the <function> tag to specify the name of a help topic for a function.

Regards