Please accept my apologies for misleading you.
The approach shown in the KB article is not applicable for version 3.6. However we've logged a bug for the whole Sitefinity backend as AM/ PM is not shown almost nowhere. We took care for this in version 5.0 for the Forums module and we will fix it for the whole Sitefinity Backend for the next Service Pack.
Please accept my apologoies for the caused inconvenience.
the Telerik team
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