When I use this Timezone_ConvertTimezoneById the extension is throwing at me the following exception:

The conversion could not be completed because the supplied DateTime did not have the Kind property set correctly.  For example, when the Kind property is DateTimeKind.Local, the source time zone must be TimeZoneInfo.Local.
Parameter name: sourceTimeZone

I'm running this on my Personal and trying to understand where should I tweak to make this work :) 

here are some screenshots
Service Center

Service Studio

Why I need to convert: In the front end I'm selecting a full day and the date-time in the server is offset by 1 hour. So, When I select Oct 21, it gives me the Oct 20.