I can only find how to write and read values (from the documentation), not edit.
quote:
The following example writes a value called "EnableOpt" in the registry and read it back.
//Write the value
var Shell = new ActiveXObject("WScript.Shell");
var ValRegPath = MsgPlus.ScriptRegPath + "EnableOpt";
Shell.RegWrite(ValRegPath, 1);
//Read the value
var EnableOpt = Shell.RegRead(ValRegPath);
Debug.Trace("EnableOpt current value: " + EnableOpt);