How do I grant access to a IIS 5.1 web site to allow writing to an xml file.

Hi;

I am trying to debug a ASP.net web application through an IIS web site on my local machine.

 I am copying contents from an xml file to another on my local c:\ drive.

And this works fine when I use the ASP.net built in web server but now that I have created my project as an IIS 5.1 web site and am stepping through its code in debug mode I don't have access rights to this file any more.

This is obviously an IIS safety feature but how to I grant premission and to which account do I grant this permission to ?

Thanks for your insights !