Impossible to lock a document after approval signature in third party plugin

Hello!

I'm developing a third party plugin for creating digital sigantures in documents.

It's based on the example from Adobe Acrobat SDK - DocSign Plugin.

In my plugin I don't need dialog "Sign as..." due to my own custom dialog.

Therefore in the DocSign plugin in the function DSEngine::sigGetSigProperties(PSSigSigPropParams params) I do such initialization:

params->outDialogStatus = kPSSigDialogNone;

Then when I create a certification signature with this DocSign plugin Acrobat offers the dialog with permitted actions after signing, and it's OK.

But when I create an approval signature Acrobat doesn't offer similar dialog with the option to lock a document after signing. As a result it's impossible to lock a document at all.

Is it correct Acrobat behavior for approval signature?

How can I lock programmatically a document after approval signature? May be I need to make other initialization in plugin?