Thanks, the project should be sent without executable indeed.
I think you should do this differently. If you want a property in your script form, you should actually create the property in your form class.
My suggestion is that you inherit a class from TScriptForm and declare the CustomProps property in it.
TMyScriptForm = class(TScriptForm)
...
property CustomProps: TStrings read GetCustomProps write SetCustomProps;
Then you change your default script form class to the new one:
IDEScripter.ScriptFormClass := TMyScriptForm;