I want to Move the cursor right one step in Word

In VBA the code is

Selection.MoveRight Unit:=wdCharacter, Count:=1

I figured out that the OLE2 can be written as

args:= ole2.create_arglist;
ole2.add_args(args,1); --Unit :=wdCharacter
ole2.add_args(args,1); --Count:=1
ole2.invoke(MySelection, 'MoveRight', args);

This works - but I only figured it out by trail and error - there must be an easier way to find the numbers for the arglist - but how?

I have see that the parameter number for xlCenter in Excel is -4108 - how have they found this number?