I’m still not quite sure why you are persisting in using Powershell when there are native actionscript commands to achieve what you want.
Also, unless formatted as code, the forum can get confused by a backslash so, to clarify, is the key you want
HKEY_LOCAL_MACHINE\SYSTEM\KES{9b03c1d9-3138-44ed-9fae-d9f4c034b88d}{16e0423f-7058-48c9-a204-725362b67639}\Default
or
HKEY_LOCAL_MACHINE\SYSTEM\KES\{9b03c1d9-3138-44ed-9fae-d9f4c034b88d}{16e0423f-7058-48c9-a204-725362b67639}\Default
As for relevance substitutions, see this post by @JasonWalker
To help further we need your actionscript formatted as code - the </> button