I am afraid that creation of custom commands is not possible at this point. My suggestion for your scenario is to create your own command that will use the RadDocumentEditor to manipulate the document. RadDocumentEditor has properties like RespectDocumentProtection which will allow execution of its methods over protected document.
Could you provide more information on what exactly is your scenario with Insert and Delete commands and how you would like to change the way they are executed. This way we will be able to assist you better.
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