Powershell V2 Group Policy cmdlets (set-gppermissions) question on deny apply?

The AD and GP cmdlets are very cool, however for the group policy there isn't an explicit deny apply.  Wondering if anyone has found a viable workaround to deny apply for groups within this specifc cmdlet?  Any help would be greatly appreciated!
-PermissionLevel <GPPermisssionType> Specifies the permission level to set for the security principal. The valid permission levels are: GpoRead, GpoApply, GpoEdit, GpoEditDeleteModifySecurity or None.

I'm not sure what cmdlets you are talking about. Vanilla PS does not have AD or GP cmdlets.

Sorry, should have explained, the builtin functionality of Windows 2008 R2 has full support for Active Directory administration and group policy administative functionality.  The new framework for Active Directory Management Gateway Service:
http://www.microsoft.com/downloads/details.aspx?FamilyID=008940c6-0296-4597-be3e-1d24c1cf0dda&displaylang=en
Provides cmdlets to administer AD etc.  One of the group policy cmdlets "Set-GPPermissions" : http://technet.microsoft.com/en-us/library/ee461038.aspx
Has almost all the functionality one could one, except the deny apply, and was wondering if anyone had found a viable workaround with the native cmdlets using R2 modules?

http://www.microsoft.com/downloads/details.aspx?FamilyID=008940c6-0296-4597-be3e-1d24c1cf0dda&displaylang=en
Provides the communciation components for the AD cmdlets in R2 for 2003 and 2008 etc.  In R2 the cmdlets are installed when the services or RSAT is installed.

Actually just found out you can use the -permissionlevel none to clear and then use -permissionlevel gpoedit, it will have the apply gpo unchecked, so in theory that should work out well.

Thanks Charles for the help on that, didn't think about clearing the flag first then setting perms.