Change Registry Permission by Script

I am supporting a number of users who are only Power Users of their local
computer. They are running Windows XP Sp2. As a result, they cannot make
changes to the "Local Machine" portion of their registry.
When it was decided that users should work as Power Users rather than local
administrators, we used the CACL.exe command to run a script that would
change the permission on a specific folder or file on the hard drive. We
need to do the same thing with at least one, if not two keys in the "Local
Machine" section of the registry.
Can permissions on registry keys be changed by script? Can the CACL.exe
command be used or is there a different tool to be used for this purpose?
Either way, what syntax would I utlize to accomplish this?
Any insights would be appreciated.