can not add custom permission in plesk

[hidenmagic]

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE: Plesk 9.0.1

PROBLEM DESCRIPTION AND STEPS TO REPRODUCE:
- i find hosting_template.xml in etc folder
- i want to add network service and aspnet user to httpdocs folder. So, i try to plus these:

<Entry AccounType="0" Account="NetworkService" Path="[HTTPD_VHOSTS_D]" AceFlags="ThisFolderSubfoldersAndFiles" AccessMask="Modify" EntryFlags="0x140" Tag="DomainUser" Tag2="" />
<Entry AccounType="0" Account="ASPNET" Path="[HTTPD_VHOSTS_D]" AceFlags="ThisFolderSubfoldersAndFiles" AccessMask="Modify" EntryFlags="0x140" Tag="DomainUser" Tag2="" />

ACTUAL RESULT

Unable to update hosting preferences: Unable to create directories: vhostmng failed: Unknown account name: ASPNET, known names are:
AccountOps
Administrator
Administrators
AnonymousLogon
AuthenticatedUser
BackupOps
Batch
CreatorGroup
CreatorGroupServer
CreatorOwner
CreatorOwnerServer
Dialup
Everyone
Guest
Guests
Interactive
Local
LocalService
Network
NetworkService
Null
PowerUsers
PreW2kCompAccess
PrintOps
Proxy
RasServers
RemoteDesktopUsers
Replicator
RestrictedCode
Self
ServerLogon
Service
System
SystemOps
TerminalServer
ThisOrganization
Users

EXPECTED RESULT:
i just want to have aspnet and network service have modify permission to httpdocs folder and any child folders of httpdocs

can any body help me?