WIX directory access rights ,Permissions

I'm building a wix setup that will install a web site
one requirement is "Netork Service" user read/write access to Images folder
(to upload Images and read uploaded images)

This can be accomplished with Permission element...

Steps
1-create a component inside the directory that permission attributes will be given
2-Inside component create permission node
(properities and details for Permission element see http://wix.sourceforge.net/manual-wix2/wix_xsd_permission.htm)
3-put apporiate componentref element to Featres node

code snippet below

directory id="Images" name="Images" guid="84A264EF-2BC5-41e3-8124-2CA10C2805DB"
createfolder directory="Images"
permission user="NETWORK SERVICE" genericall="yes"
/createfolder

...
feature id="ImagesFolderComponent" level="1"
............