Keeping transparency when exporting Layer comps to File

[retouchbox]

Hi guys, I am a noob with scripting but I modified Layer comps to File script. The script works well but I am missing the ''save transparency'' option. I don't know what command and where should be added. 

In the PSD I have the product in grey (no background) and above I have colour groups - black, red, blue etc. The script is exporting very well to TIFF but it does not hold transparency at the end.

This option is visible when saving as. If anyone can put here code and let me know where to implemented it? I know that this shortcut and I have to use script guide etc but I am almost 40 and learning new things coming very hard. So if you are able help, thanks so much.