Set value to a Hidden Field

How can I map a Hidden Field object and set it's value in a Keyword test? Below is how my hidden object look like. I did see a post that I can access hidden objects if I turn on Hybrid Mode. However, I don't see a Hybrid Mode setting in the Project Properties but instead I see only Hybrid Mobile option.

<input id="generateDoc" name="Product.GenerateDocuments" type="hidden" value="false">

In real world this action will not be performed a by user in UI however, I need this to identify if the request is coming from an actual User or from a Key word test. I know we could use different set of User accounts but that is not an option in my case.

Any help on this is very much appreciated.

Thanks!