unfortunately, the searching of PDF and DOC files has not yet been implemented, though it is planned and we have already started to work on it. At this moment, we do not have a fixed date at which the feature will be released, but since the work on implementation has already started I would say that the feature will most probably be released with Sitefinity 4.0, our next major release, due to be released next year.
I hope you'll find this information helpful. Let us know if there is anything else we can do for you.
the Telerik team
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