External Style Sheet with Epub export from Indesign Server

Where do I have to place the CSS-file when I want to export to ePub with external style sheet option with InDesign Server CS5? Or can I use a absolute/relative path to the destination of the CSS-file? I use the following JavaScript to define the export options:

opts.styleHandling = OEBExportOptions.extStyleSheet;
opts.styleSheet = 'template.css'

Please an example.

Regards, Sjoerd