What is the best way to search through comments using acrobat plugin SDK?

Hello,

I used Search APIs to search through comments:

Here is my code snippet:

ASText searchKey;
searchKey = ASTextFromUnicode((ASUTF16Val*)reqText, kUTF16HostEndian);
SearchQueryDataRec srcQuery;
memset(&srcQuery, 0, sizeof(SearchQueryDataRec));
srcQuery.size = sizeof(SearchQueryDataRec);
srcQuery.query = searchKey;
srcQuery.type = kSearchActiveDoc;
srcQuery.scope = kSearchDocumentText | kSearchMarkup;
srcQuery.maxDocs = 1;
SearchExecuteQueryEx(&srcQuery);
ASTextDestroy(searchKey);

As per the documentation, kSearchMarkup option is used to search markups (In my case,annotations).

But it is not searching through annotation comments.

It gives me "Not found" error in a search panel at left.

Where am I wrong in this code?

Thank you in advance!